diff --git a/doc/api/deprecations.md b/doc/api/deprecations.md
index 8461caabfc56ee..ddfe9c4adc7250 100644
--- a/doc/api/deprecations.md
+++ b/doc/api/deprecations.md
@@ -590,6 +590,22 @@ Type: Runtime
 `node debug` corresponds to the legacy CLI debugger which has been replaced with
 a V8-inspector based CLI debugger available through `node inspect`.
 
+<a id="DEP00XX"></a>
+### DEP00XX: Usage of _stream_*
+
+Type: Runtime
+
+Using `require('_stream_readable')`,
+`require('_stream_writable')`, `require('_stream_duplex')`
+`require('_stream_transform')`, `require('_stream_passthrough')`
+is now deprecated. The same content are available through:
+`require('stream').Readable`, `require('stream').Writable`,
+`require('stream').Duplex`, `require('stream').Transform`,
+`require('stream').PassThrough`.
+
+*Note*: The usage of `_stream` prefixed modules from core was never
+documented.
+
 [alloc]: buffer.html#buffer_class_method_buffer_alloc_size_fill_encoding
 [alloc_unsafe_size]: buffer.html#buffer_class_method_buffer_allocunsafe_size
 [`Buffer.allocUnsafeSlow(size)`]: buffer.html#buffer_class_method_buffer_allocunsafeslow_size
diff --git a/lib/_stream_duplex.js b/lib/_stream_duplex.js
index 4422b62aac3250..8487eda2076e1d 100644
--- a/lib/_stream_duplex.js
+++ b/lib/_stream_duplex.js
@@ -1,78 +1,6 @@
-// Copyright Joyent, Inc. and other Node contributors.
-//
-// Permission is hereby granted, free of charge, to any person obtaining a
-// copy of this software and associated documentation files (the
-// "Software"), to deal in the Software without restriction, including
-// without limitation the rights to use, copy, modify, merge, publish,
-// distribute, sublicense, and/or sell copies of the Software, and to permit
-// persons to whom the Software is furnished to do so, subject to the
-// following conditions:
-//
-// The above copyright notice and this permission notice shall be included
-// in all copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
-// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
-// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
-// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
-// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
-// USE OR OTHER DEALINGS IN THE SOFTWARE.
-
-// a duplex stream is just a stream that is both readable and writable.
-// Since JS doesn't have multiple prototypal inheritance, this class
-// prototypally inherits from Readable, and then parasitically from
-// Writable.
-
 'use strict';
 
-module.exports = Duplex;
-
-const util = require('util');
-const Readable = require('_stream_readable');
-const Writable = require('_stream_writable');
-
-util.inherits(Duplex, Readable);
-
-var keys = Object.keys(Writable.prototype);
-for (var v = 0; v < keys.length; v++) {
-  var method = keys[v];
-  if (!Duplex.prototype[method])
-    Duplex.prototype[method] = Writable.prototype[method];
-}
-
-function Duplex(options) {
-  if (!(this instanceof Duplex))
-    return new Duplex(options);
-
-  Readable.call(this, options);
-  Writable.call(this, options);
-
-  if (options && options.readable === false)
-    this.readable = false;
-
-  if (options && options.writable === false)
-    this.writable = false;
-
-  this.allowHalfOpen = true;
-  if (options && options.allowHalfOpen === false)
-    this.allowHalfOpen = false;
-
-  this.once('end', onend);
-}
-
-// the no-half-open enforcer
-function onend() {
-  // if we allow half-open state, or if the writable side ended,
-  // then we're ok.
-  if (this.allowHalfOpen || this._writableState.ended)
-    return;
-
-  // no more data can be written.
-  // But allow more writes to happen in this tick.
-  process.nextTick(onEndNT, this);
-}
+process.emitWarning(`The ${__filename} module is deprecated. Please use stream`,
+                    'DeprecationWarning', 'DEP00XX');
 
-function onEndNT(self) {
-  self.end();
-}
+module.exports = require('internal/streams/duplex');
diff --git a/lib/_stream_passthrough.js b/lib/_stream_passthrough.js
index 82adaa8d1c7d86..0695ca3da84d99 100644
--- a/lib/_stream_passthrough.js
+++ b/lib/_stream_passthrough.js
@@ -1,43 +1,6 @@
-// Copyright Joyent, Inc. and other Node contributors.
-//
-// Permission is hereby granted, free of charge, to any person obtaining a
-// copy of this software and associated documentation files (the
-// "Software"), to deal in the Software without restriction, including
-// without limitation the rights to use, copy, modify, merge, publish,
-// distribute, sublicense, and/or sell copies of the Software, and to permit
-// persons to whom the Software is furnished to do so, subject to the
-// following conditions:
-//
-// The above copyright notice and this permission notice shall be included
-// in all copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
-// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
-// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
-// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
-// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
-// USE OR OTHER DEALINGS IN THE SOFTWARE.
-
-// a passthrough stream.
-// basically just the most minimal sort of Transform stream.
-// Every written chunk gets output as-is.
-
 'use strict';
 
-module.exports = PassThrough;
-
-const Transform = require('_stream_transform');
-const util = require('util');
-util.inherits(PassThrough, Transform);
-
-function PassThrough(options) {
-  if (!(this instanceof PassThrough))
-    return new PassThrough(options);
-
-  Transform.call(this, options);
-}
+process.emitWarning(`The ${__filename} module is deprecated. Please use stream`,
+                    'DeprecationWarning', 'DEP00XX');
 
-PassThrough.prototype._transform = function(chunk, encoding, cb) {
-  cb(null, chunk);
-};
+module.exports = require('internal/streams/passthrough');
diff --git a/lib/_stream_readable.js b/lib/_stream_readable.js
index 879e5ddb53fe40..19e7a41b26e1af 100644
--- a/lib/_stream_readable.js
+++ b/lib/_stream_readable.js
@@ -1,994 +1,6 @@
-// Copyright Joyent, Inc. and other Node contributors.
-//
-// Permission is hereby granted, free of charge, to any person obtaining a
-// copy of this software and associated documentation files (the
-// "Software"), to deal in the Software without restriction, including
-// without limitation the rights to use, copy, modify, merge, publish,
-// distribute, sublicense, and/or sell copies of the Software, and to permit
-// persons to whom the Software is furnished to do so, subject to the
-// following conditions:
-//
-// The above copyright notice and this permission notice shall be included
-// in all copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
-// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
-// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
-// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
-// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
-// USE OR OTHER DEALINGS IN THE SOFTWARE.
-
 'use strict';
 
-module.exports = Readable;
-Readable.ReadableState = ReadableState;
-
-const EE = require('events');
-const Stream = require('stream');
-const Buffer = require('buffer').Buffer;
-const util = require('util');
-const debug = util.debuglog('stream');
-const BufferList = require('internal/streams/BufferList');
-var StringDecoder;
-
-util.inherits(Readable, Stream);
-
-const kProxyEvents = ['error', 'close', 'destroy', 'pause', 'resume'];
-
-function prependListener(emitter, event, fn) {
-  // Sadly this is not cacheable as some libraries bundle their own
-  // event emitter implementation with them.
-  if (typeof emitter.prependListener === 'function') {
-    return emitter.prependListener(event, fn);
-  } else {
-    // This is a hack to make sure that our error handler is attached before any
-    // userland ones.  NEVER DO THIS. This is here only because this code needs
-    // to continue to work with older versions of Node.js that do not include
-    // the prependListener() method. The goal is to eventually remove this hack.
-    if (!emitter._events || !emitter._events[event])
-      emitter.on(event, fn);
-    else if (Array.isArray(emitter._events[event]))
-      emitter._events[event].unshift(fn);
-    else
-      emitter._events[event] = [fn, emitter._events[event]];
-  }
-}
-
-function ReadableState(options, stream) {
-  options = options || {};
-
-  // object stream flag. Used to make read(n) ignore n and to
-  // make all the buffer merging and length checks go away
-  this.objectMode = !!options.objectMode;
-
-  if (stream instanceof Stream.Duplex)
-    this.objectMode = this.objectMode || !!options.readableObjectMode;
-
-  // the point at which it stops calling _read() to fill the buffer
-  // Note: 0 is a valid value, means "don't call _read preemptively ever"
-  var hwm = options.highWaterMark;
-  var defaultHwm = this.objectMode ? 16 : 16 * 1024;
-  this.highWaterMark = (hwm || hwm === 0) ? hwm : defaultHwm;
-
-  // cast to ints.
-  this.highWaterMark = ~~this.highWaterMark;
-
-  // A linked list is used to store data chunks instead of an array because the
-  // linked list can remove elements from the beginning faster than
-  // array.shift()
-  this.buffer = new BufferList();
-  this.length = 0;
-  this.pipes = null;
-  this.pipesCount = 0;
-  this.flowing = null;
-  this.ended = false;
-  this.endEmitted = false;
-  this.reading = false;
-
-  // a flag to be able to tell if the event 'readable'/'data' is emitted
-  // immediately, or on a later tick.  We set this to true at first, because
-  // any actions that shouldn't happen until "later" should generally also
-  // not happen before the first read call.
-  this.sync = true;
-
-  // whenever we return null, then we set a flag to say
-  // that we're awaiting a 'readable' event emission.
-  this.needReadable = false;
-  this.emittedReadable = false;
-  this.readableListening = false;
-  this.resumeScheduled = false;
-
-  // Crypto is kind of old and crusty.  Historically, its default string
-  // encoding is 'binary' so we have to make this configurable.
-  // Everything else in the universe uses 'utf8', though.
-  this.defaultEncoding = options.defaultEncoding || 'utf8';
-
-  // the number of writers that are awaiting a drain event in .pipe()s
-  this.awaitDrain = 0;
-
-  // if true, a maybeReadMore has been scheduled
-  this.readingMore = false;
-
-  this.decoder = null;
-  this.encoding = null;
-  if (options.encoding) {
-    if (!StringDecoder)
-      StringDecoder = require('string_decoder').StringDecoder;
-    this.decoder = new StringDecoder(options.encoding);
-    this.encoding = options.encoding;
-  }
-}
-
-function Readable(options) {
-  if (!(this instanceof Readable))
-    return new Readable(options);
-
-  this._readableState = new ReadableState(options, this);
-
-  // legacy
-  this.readable = true;
-
-  if (options && typeof options.read === 'function')
-    this._read = options.read;
-
-  Stream.call(this);
-}
-
-// Manually shove something into the read() buffer.
-// This returns true if the highWaterMark has not been hit yet,
-// similar to how Writable.write() returns true if you should
-// write() some more.
-Readable.prototype.push = function(chunk, encoding) {
-  var state = this._readableState;
-
-  if (!state.objectMode && typeof chunk === 'string') {
-    encoding = encoding || state.defaultEncoding;
-    if (encoding !== state.encoding) {
-      chunk = Buffer.from(chunk, encoding);
-      encoding = '';
-    }
-  }
-
-  return readableAddChunk(this, state, chunk, encoding, false);
-};
-
-// Unshift should *always* be something directly out of read()
-Readable.prototype.unshift = function(chunk) {
-  var state = this._readableState;
-  return readableAddChunk(this, state, chunk, '', true);
-};
-
-Readable.prototype.isPaused = function() {
-  return this._readableState.flowing === false;
-};
-
-function readableAddChunk(stream, state, chunk, encoding, addToFront) {
-  var er = chunkInvalid(state, chunk);
-  if (er) {
-    stream.emit('error', er);
-  } else if (chunk === null) {
-    state.reading = false;
-    onEofChunk(stream, state);
-  } else if (state.objectMode || chunk && chunk.length > 0) {
-    if (state.ended && !addToFront) {
-      const e = new Error('stream.push() after EOF');
-      stream.emit('error', e);
-    } else if (state.endEmitted && addToFront) {
-      const e = new Error('stream.unshift() after end event');
-      stream.emit('error', e);
-    } else {
-      var skipAdd;
-      if (state.decoder && !addToFront && !encoding) {
-        chunk = state.decoder.write(chunk);
-        skipAdd = (!state.objectMode && chunk.length === 0);
-      }
-
-      if (!addToFront)
-        state.reading = false;
-
-      // Don't add to the buffer if we've decoded to an empty string chunk and
-      // we're not in object mode
-      if (!skipAdd) {
-        // if we want the data now, just emit it.
-        if (state.flowing && state.length === 0 && !state.sync) {
-          stream.emit('data', chunk);
-          stream.read(0);
-        } else {
-          // update the buffer info.
-          state.length += state.objectMode ? 1 : chunk.length;
-          if (addToFront)
-            state.buffer.unshift(chunk);
-          else
-            state.buffer.push(chunk);
-
-          if (state.needReadable)
-            emitReadable(stream);
-        }
-      }
-
-      maybeReadMore(stream, state);
-    }
-  } else if (!addToFront) {
-    state.reading = false;
-  }
-
-  return needMoreData(state);
-}
-
-
-// if it's past the high water mark, we can push in some more.
-// Also, if we have no data yet, we can stand some
-// more bytes.  This is to work around cases where hwm=0,
-// such as the repl.  Also, if the push() triggered a
-// readable event, and the user called read(largeNumber) such that
-// needReadable was set, then we ought to push more, so that another
-// 'readable' event will be triggered.
-function needMoreData(state) {
-  return !state.ended &&
-         (state.needReadable ||
-          state.length < state.highWaterMark ||
-          state.length === 0);
-}
-
-// backwards compatibility.
-Readable.prototype.setEncoding = function(enc) {
-  if (!StringDecoder)
-    StringDecoder = require('string_decoder').StringDecoder;
-  this._readableState.decoder = new StringDecoder(enc);
-  this._readableState.encoding = enc;
-  return this;
-};
-
-// Don't raise the hwm > 8MB
-const MAX_HWM = 0x800000;
-function computeNewHighWaterMark(n) {
-  if (n >= MAX_HWM) {
-    n = MAX_HWM;
-  } else {
-    // Get the next highest power of 2 to prevent increasing hwm excessively in
-    // tiny amounts
-    n--;
-    n |= n >>> 1;
-    n |= n >>> 2;
-    n |= n >>> 4;
-    n |= n >>> 8;
-    n |= n >>> 16;
-    n++;
-  }
-  return n;
-}
-
-// This function is designed to be inlinable, so please take care when making
-// changes to the function body.
-function howMuchToRead(n, state) {
-  if (n <= 0 || (state.length === 0 && state.ended))
-    return 0;
-  if (state.objectMode)
-    return 1;
-  if (n !== n) {
-    // Only flow one buffer at a time
-    if (state.flowing && state.length)
-      return state.buffer.head.data.length;
-    else
-      return state.length;
-  }
-  // If we're asking for more than the current hwm, then raise the hwm.
-  if (n > state.highWaterMark)
-    state.highWaterMark = computeNewHighWaterMark(n);
-  if (n <= state.length)
-    return n;
-  // Don't have enough
-  if (!state.ended) {
-    state.needReadable = true;
-    return 0;
-  }
-  return state.length;
-}
-
-// you can override either this method, or the async _read(n) below.
-Readable.prototype.read = function(n) {
-  debug('read', n);
-  n = parseInt(n, 10);
-  var state = this._readableState;
-  var nOrig = n;
-
-  if (n !== 0)
-    state.emittedReadable = false;
-
-  // if we're doing read(0) to trigger a readable event, but we
-  // already have a bunch of data in the buffer, then just trigger
-  // the 'readable' event and move on.
-  if (n === 0 &&
-      state.needReadable &&
-      (state.length >= state.highWaterMark || state.ended)) {
-    debug('read: emitReadable', state.length, state.ended);
-    if (state.length === 0 && state.ended)
-      endReadable(this);
-    else
-      emitReadable(this);
-    return null;
-  }
-
-  n = howMuchToRead(n, state);
-
-  // if we've ended, and we're now clear, then finish it up.
-  if (n === 0 && state.ended) {
-    if (state.length === 0)
-      endReadable(this);
-    return null;
-  }
-
-  // All the actual chunk generation logic needs to be
-  // *below* the call to _read.  The reason is that in certain
-  // synthetic stream cases, such as passthrough streams, _read
-  // may be a completely synchronous operation which may change
-  // the state of the read buffer, providing enough data when
-  // before there was *not* enough.
-  //
-  // So, the steps are:
-  // 1. Figure out what the state of things will be after we do
-  // a read from the buffer.
-  //
-  // 2. If that resulting state will trigger a _read, then call _read.
-  // Note that this may be asynchronous, or synchronous.  Yes, it is
-  // deeply ugly to write APIs this way, but that still doesn't mean
-  // that the Readable class should behave improperly, as streams are
-  // designed to be sync/async agnostic.
-  // Take note if the _read call is sync or async (ie, if the read call
-  // has returned yet), so that we know whether or not it's safe to emit
-  // 'readable' etc.
-  //
-  // 3. Actually pull the requested chunks out of the buffer and return.
-
-  // if we need a readable event, then we need to do some reading.
-  var doRead = state.needReadable;
-  debug('need readable', doRead);
-
-  // if we currently have less than the highWaterMark, then also read some
-  if (state.length === 0 || state.length - n < state.highWaterMark) {
-    doRead = true;
-    debug('length less than watermark', doRead);
-  }
-
-  // however, if we've ended, then there's no point, and if we're already
-  // reading, then it's unnecessary.
-  if (state.ended || state.reading) {
-    doRead = false;
-    debug('reading or ended', doRead);
-  } else if (doRead) {
-    debug('do read');
-    state.reading = true;
-    state.sync = true;
-    // if the length is currently zero, then we *need* a readable event.
-    if (state.length === 0)
-      state.needReadable = true;
-    // call internal read method
-    this._read(state.highWaterMark);
-    state.sync = false;
-    // If _read pushed data synchronously, then `reading` will be false,
-    // and we need to re-evaluate how much data we can return to the user.
-    if (!state.reading)
-      n = howMuchToRead(nOrig, state);
-  }
-
-  var ret;
-  if (n > 0)
-    ret = fromList(n, state);
-  else
-    ret = null;
-
-  if (ret === null) {
-    state.needReadable = true;
-    n = 0;
-  } else {
-    state.length -= n;
-  }
-
-  if (state.length === 0) {
-    // If we have nothing in the buffer, then we want to know
-    // as soon as we *do* get something into the buffer.
-    if (!state.ended)
-      state.needReadable = true;
-
-    // If we tried to read() past the EOF, then emit end on the next tick.
-    if (nOrig !== n && state.ended)
-      endReadable(this);
-  }
-
-  if (ret !== null)
-    this.emit('data', ret);
-
-  return ret;
-};
-
-function chunkInvalid(state, chunk) {
-  var er = null;
-  if (!(chunk instanceof Buffer) &&
-      typeof chunk !== 'string' &&
-      chunk !== null &&
-      chunk !== undefined &&
-      !state.objectMode) {
-    er = new TypeError('Invalid non-string/buffer chunk');
-  }
-  return er;
-}
-
-
-function onEofChunk(stream, state) {
-  if (state.ended) return;
-  if (state.decoder) {
-    var chunk = state.decoder.end();
-    if (chunk && chunk.length) {
-      state.buffer.push(chunk);
-      state.length += state.objectMode ? 1 : chunk.length;
-    }
-  }
-  state.ended = true;
-
-  // emit 'readable' now to make sure it gets picked up.
-  emitReadable(stream);
-}
-
-// Don't emit readable right away in sync mode, because this can trigger
-// another read() call => stack overflow.  This way, it might trigger
-// a nextTick recursion warning, but that's not so bad.
-function emitReadable(stream) {
-  var state = stream._readableState;
-  state.needReadable = false;
-  if (!state.emittedReadable) {
-    debug('emitReadable', state.flowing);
-    state.emittedReadable = true;
-    if (state.sync)
-      process.nextTick(emitReadable_, stream);
-    else
-      emitReadable_(stream);
-  }
-}
-
-function emitReadable_(stream) {
-  debug('emit readable');
-  stream.emit('readable');
-  flow(stream);
-}
-
-
-// at this point, the user has presumably seen the 'readable' event,
-// and called read() to consume some data.  that may have triggered
-// in turn another _read(n) call, in which case reading = true if
-// it's in progress.
-// However, if we're not ended, or reading, and the length < hwm,
-// then go ahead and try to read some more preemptively.
-function maybeReadMore(stream, state) {
-  if (!state.readingMore) {
-    state.readingMore = true;
-    process.nextTick(maybeReadMore_, stream, state);
-  }
-}
-
-function maybeReadMore_(stream, state) {
-  var len = state.length;
-  while (!state.reading && !state.flowing && !state.ended &&
-         state.length < state.highWaterMark) {
-    debug('maybeReadMore read 0');
-    stream.read(0);
-    if (len === state.length)
-      // didn't get any data, stop spinning.
-      break;
-    else
-      len = state.length;
-  }
-  state.readingMore = false;
-}
-
-// abstract method.  to be overridden in specific implementation classes.
-// call cb(er, data) where data is <= n in length.
-// for virtual (non-string, non-buffer) streams, "length" is somewhat
-// arbitrary, and perhaps not very meaningful.
-Readable.prototype._read = function(n) {
-  this.emit('error', new Error('_read() is not implemented'));
-};
-
-Readable.prototype.pipe = function(dest, pipeOpts) {
-  var src = this;
-  var state = this._readableState;
-
-  switch (state.pipesCount) {
-    case 0:
-      state.pipes = dest;
-      break;
-    case 1:
-      state.pipes = [state.pipes, dest];
-      break;
-    default:
-      state.pipes.push(dest);
-      break;
-  }
-  state.pipesCount += 1;
-  debug('pipe count=%d opts=%j', state.pipesCount, pipeOpts);
-
-  var doEnd = (!pipeOpts || pipeOpts.end !== false) &&
-              dest !== process.stdout &&
-              dest !== process.stderr;
-
-  var endFn = doEnd ? onend : unpipe;
-  if (state.endEmitted)
-    process.nextTick(endFn);
-  else
-    src.once('end', endFn);
-
-  dest.on('unpipe', onunpipe);
-  function onunpipe(readable) {
-    debug('onunpipe');
-    if (readable === src) {
-      cleanup();
-    }
-  }
-
-  function onend() {
-    debug('onend');
-    dest.end();
-  }
-
-  // when the dest drains, it reduces the awaitDrain counter
-  // on the source.  This would be more elegant with a .once()
-  // handler in flow(), but adding and removing repeatedly is
-  // too slow.
-  var ondrain = pipeOnDrain(src);
-  dest.on('drain', ondrain);
-
-  var cleanedUp = false;
-  function cleanup() {
-    debug('cleanup');
-    // cleanup event handlers once the pipe is broken
-    dest.removeListener('close', onclose);
-    dest.removeListener('finish', onfinish);
-    dest.removeListener('drain', ondrain);
-    dest.removeListener('error', onerror);
-    dest.removeListener('unpipe', onunpipe);
-    src.removeListener('end', onend);
-    src.removeListener('end', unpipe);
-    src.removeListener('data', ondata);
-
-    cleanedUp = true;
-
-    // if the reader is waiting for a drain event from this
-    // specific writer, then it would cause it to never start
-    // flowing again.
-    // So, if this is awaiting a drain, then we just call it now.
-    // If we don't know, then assume that we are waiting for one.
-    if (state.awaitDrain &&
-        (!dest._writableState || dest._writableState.needDrain))
-      ondrain();
-  }
-
-  // If the user pushes more data while we're writing to dest then we'll end up
-  // in ondata again. However, we only want to increase awaitDrain once because
-  // dest will only emit one 'drain' event for the multiple writes.
-  // => Introduce a guard on increasing awaitDrain.
-  var increasedAwaitDrain = false;
-  src.on('data', ondata);
-  function ondata(chunk) {
-    debug('ondata');
-    increasedAwaitDrain = false;
-    var ret = dest.write(chunk);
-    if (false === ret && !increasedAwaitDrain) {
-      // If the user unpiped during `dest.write()`, it is possible
-      // to get stuck in a permanently paused state if that write
-      // also returned false.
-      // => Check whether `dest` is still a piping destination.
-      if (((state.pipesCount === 1 && state.pipes === dest) ||
-           (state.pipesCount > 1 && state.pipes.indexOf(dest) !== -1)) &&
-          !cleanedUp) {
-        debug('false write response, pause', src._readableState.awaitDrain);
-        src._readableState.awaitDrain++;
-        increasedAwaitDrain = true;
-      }
-      src.pause();
-    }
-  }
-
-  // if the dest has an error, then stop piping into it.
-  // however, don't suppress the throwing behavior for this.
-  function onerror(er) {
-    debug('onerror', er);
-    unpipe();
-    dest.removeListener('error', onerror);
-    if (EE.listenerCount(dest, 'error') === 0)
-      dest.emit('error', er);
-  }
-
-  // Make sure our error handler is attached before userland ones.
-  prependListener(dest, 'error', onerror);
-
-  // Both close and finish should trigger unpipe, but only once.
-  function onclose() {
-    dest.removeListener('finish', onfinish);
-    unpipe();
-  }
-  dest.once('close', onclose);
-  function onfinish() {
-    debug('onfinish');
-    dest.removeListener('close', onclose);
-    unpipe();
-  }
-  dest.once('finish', onfinish);
-
-  function unpipe() {
-    debug('unpipe');
-    src.unpipe(dest);
-  }
-
-  // tell the dest that it's being piped to
-  dest.emit('pipe', src);
-
-  // start the flow if it hasn't been started already.
-  if (!state.flowing) {
-    debug('pipe resume');
-    src.resume();
-  }
-
-  return dest;
-};
-
-function pipeOnDrain(src) {
-  return function() {
-    var state = src._readableState;
-    debug('pipeOnDrain', state.awaitDrain);
-    if (state.awaitDrain)
-      state.awaitDrain--;
-    if (state.awaitDrain === 0 && EE.listenerCount(src, 'data')) {
-      state.flowing = true;
-      flow(src);
-    }
-  };
-}
-
-
-Readable.prototype.unpipe = function(dest) {
-  var state = this._readableState;
-
-  // if we're not piping anywhere, then do nothing.
-  if (state.pipesCount === 0)
-    return this;
-
-  // just one destination.  most common case.
-  if (state.pipesCount === 1) {
-    // passed in one, but it's not the right one.
-    if (dest && dest !== state.pipes)
-      return this;
-
-    if (!dest)
-      dest = state.pipes;
-
-    // got a match.
-    state.pipes = null;
-    state.pipesCount = 0;
-    state.flowing = false;
-    if (dest)
-      dest.emit('unpipe', this);
-    return this;
-  }
-
-  // slow case. multiple pipe destinations.
-
-  if (!dest) {
-    // remove all.
-    var dests = state.pipes;
-    var len = state.pipesCount;
-    state.pipes = null;
-    state.pipesCount = 0;
-    state.flowing = false;
-
-    for (var i = 0; i < len; i++)
-      dests[i].emit('unpipe', this);
-    return this;
-  }
-
-  // try to find the right one.
-  var index = state.pipes.indexOf(dest);
-  if (index === -1)
-    return this;
-
-  state.pipes.splice(index, 1);
-  state.pipesCount -= 1;
-  if (state.pipesCount === 1)
-    state.pipes = state.pipes[0];
-
-  dest.emit('unpipe', this);
-
-  return this;
-};
-
-// set up data events if they are asked for
-// Ensure readable listeners eventually get something
-Readable.prototype.on = function(ev, fn) {
-  const res = Stream.prototype.on.call(this, ev, fn);
-
-  if (ev === 'data') {
-    // Start flowing on next tick if stream isn't explicitly paused
-    if (this._readableState.flowing !== false)
-      this.resume();
-  } else if (ev === 'readable') {
-    const state = this._readableState;
-    if (!state.endEmitted && !state.readableListening) {
-      state.readableListening = state.needReadable = true;
-      state.emittedReadable = false;
-      if (!state.reading) {
-        process.nextTick(nReadingNextTick, this);
-      } else if (state.length) {
-        emitReadable(this, state);
-      }
-    }
-  }
-
-  return res;
-};
-Readable.prototype.addListener = Readable.prototype.on;
-
-function nReadingNextTick(self) {
-  debug('readable nexttick read 0');
-  self.read(0);
-}
-
-// pause() and resume() are remnants of the legacy readable stream API
-// If the user uses them, then switch into old mode.
-Readable.prototype.resume = function() {
-  var state = this._readableState;
-  if (!state.flowing) {
-    debug('resume');
-    state.flowing = true;
-    resume(this, state);
-  }
-  return this;
-};
-
-function resume(stream, state) {
-  if (!state.resumeScheduled) {
-    state.resumeScheduled = true;
-    process.nextTick(resume_, stream, state);
-  }
-}
-
-function resume_(stream, state) {
-  if (!state.reading) {
-    debug('resume read 0');
-    stream.read(0);
-  }
-
-  state.resumeScheduled = false;
-  state.awaitDrain = 0;
-  stream.emit('resume');
-  flow(stream);
-  if (state.flowing && !state.reading)
-    stream.read(0);
-}
-
-Readable.prototype.pause = function() {
-  debug('call pause flowing=%j', this._readableState.flowing);
-  if (false !== this._readableState.flowing) {
-    debug('pause');
-    this._readableState.flowing = false;
-    this.emit('pause');
-  }
-  return this;
-};
-
-function flow(stream) {
-  const state = stream._readableState;
-  debug('flow', state.flowing);
-  while (state.flowing && stream.read() !== null);
-}
-
-// wrap an old-style stream as the async data source.
-// This is *not* part of the readable stream interface.
-// It is an ugly unfortunate mess of history.
-Readable.prototype.wrap = function(stream) {
-  var state = this._readableState;
-  var paused = false;
-
-  var self = this;
-  stream.on('end', function() {
-    debug('wrapped end');
-    if (state.decoder && !state.ended) {
-      var chunk = state.decoder.end();
-      if (chunk && chunk.length)
-        self.push(chunk);
-    }
-
-    self.push(null);
-  });
-
-  stream.on('data', function(chunk) {
-    debug('wrapped data');
-    if (state.decoder)
-      chunk = state.decoder.write(chunk);
-
-    // don't skip over falsy values in objectMode
-    if (state.objectMode && (chunk === null || chunk === undefined))
-      return;
-    else if (!state.objectMode && (!chunk || !chunk.length))
-      return;
-
-    var ret = self.push(chunk);
-    if (!ret) {
-      paused = true;
-      stream.pause();
-    }
-  });
-
-  // proxy all the other methods.
-  // important when wrapping filters and duplexes.
-  for (var i in stream) {
-    if (this[i] === undefined && typeof stream[i] === 'function') {
-      this[i] = function(method) {
-        return function() {
-          return stream[method].apply(stream, arguments);
-        };
-      }(i);
-    }
-  }
-
-  // proxy certain important events.
-  for (var n = 0; n < kProxyEvents.length; n++) {
-    stream.on(kProxyEvents[n], self.emit.bind(self, kProxyEvents[n]));
-  }
-
-  // when we try to consume some more bytes, simply unpause the
-  // underlying stream.
-  self._read = function(n) {
-    debug('wrapped _read', n);
-    if (paused) {
-      paused = false;
-      stream.resume();
-    }
-  };
-
-  return self;
-};
-
-
-// exposed for testing purposes only.
-Readable._fromList = fromList;
-
-// Pluck off n bytes from an array of buffers.
-// Length is the combined lengths of all the buffers in the list.
-// This function is designed to be inlinable, so please take care when making
-// changes to the function body.
-function fromList(n, state) {
-  // nothing buffered
-  if (state.length === 0)
-    return null;
-
-  var ret;
-  if (state.objectMode)
-    ret = state.buffer.shift();
-  else if (!n || n >= state.length) {
-    // read it all, truncate the list
-    if (state.decoder)
-      ret = state.buffer.join('');
-    else if (state.buffer.length === 1)
-      ret = state.buffer.head.data;
-    else
-      ret = state.buffer.concat(state.length);
-    state.buffer.clear();
-  } else {
-    // read part of list
-    ret = fromListPartial(n, state.buffer, state.decoder);
-  }
-
-  return ret;
-}
-
-// Extracts only enough buffered data to satisfy the amount requested.
-// This function is designed to be inlinable, so please take care when making
-// changes to the function body.
-function fromListPartial(n, list, hasStrings) {
-  var ret;
-  if (n < list.head.data.length) {
-    // slice is the same for buffers and strings
-    ret = list.head.data.slice(0, n);
-    list.head.data = list.head.data.slice(n);
-  } else if (n === list.head.data.length) {
-    // first chunk is a perfect match
-    ret = list.shift();
-  } else {
-    // result spans more than one buffer
-    ret = (hasStrings ?
-           copyFromBufferString(n, list) :
-           copyFromBuffer(n, list));
-  }
-  return ret;
-}
-
-// Copies a specified amount of characters from the list of buffered data
-// chunks.
-// This function is designed to be inlinable, so please take care when making
-// changes to the function body.
-function copyFromBufferString(n, list) {
-  var p = list.head;
-  var c = 1;
-  var ret = p.data;
-  n -= ret.length;
-  while (p = p.next) {
-    const str = p.data;
-    const nb = (n > str.length ? str.length : n);
-    if (nb === str.length)
-      ret += str;
-    else
-      ret += str.slice(0, n);
-    n -= nb;
-    if (n === 0) {
-      if (nb === str.length) {
-        ++c;
-        if (p.next)
-          list.head = p.next;
-        else
-          list.head = list.tail = null;
-      } else {
-        list.head = p;
-        p.data = str.slice(nb);
-      }
-      break;
-    }
-    ++c;
-  }
-  list.length -= c;
-  return ret;
-}
-
-// Copies a specified amount of bytes from the list of buffered data chunks.
-// This function is designed to be inlinable, so please take care when making
-// changes to the function body.
-function copyFromBuffer(n, list) {
-  const ret = Buffer.allocUnsafe(n);
-  var p = list.head;
-  var c = 1;
-  p.data.copy(ret);
-  n -= p.data.length;
-  while (p = p.next) {
-    const buf = p.data;
-    const nb = (n > buf.length ? buf.length : n);
-    buf.copy(ret, ret.length - n, 0, nb);
-    n -= nb;
-    if (n === 0) {
-      if (nb === buf.length) {
-        ++c;
-        if (p.next)
-          list.head = p.next;
-        else
-          list.head = list.tail = null;
-      } else {
-        list.head = p;
-        p.data = buf.slice(nb);
-      }
-      break;
-    }
-    ++c;
-  }
-  list.length -= c;
-  return ret;
-}
-
-function endReadable(stream) {
-  var state = stream._readableState;
-
-  // If we get here before consuming all the bytes, then that is a
-  // bug in node.  Should never happen.
-  if (state.length > 0)
-    throw new Error('"endReadable()" called on non-empty stream');
-
-  if (!state.endEmitted) {
-    state.ended = true;
-    process.nextTick(endReadableNT, state, stream);
-  }
-}
+process.emitWarning(`The ${__filename} module is deprecated. Please use stream`,
+                    'DeprecationWarning', 'DEP00XX');
 
-function endReadableNT(state, stream) {
-  // Check that we didn't get one last unshift.
-  if (!state.endEmitted && state.length === 0) {
-    state.endEmitted = true;
-    stream.readable = false;
-    stream.emit('end');
-  }
-}
+module.exports = require('internal/streams/readable');
diff --git a/lib/_stream_transform.js b/lib/_stream_transform.js
index 8adf3ed12d9384..0bb462ffabcc98 100644
--- a/lib/_stream_transform.js
+++ b/lib/_stream_transform.js
@@ -1,216 +1,6 @@
-// Copyright Joyent, Inc. and other Node contributors.
-//
-// Permission is hereby granted, free of charge, to any person obtaining a
-// copy of this software and associated documentation files (the
-// "Software"), to deal in the Software without restriction, including
-// without limitation the rights to use, copy, modify, merge, publish,
-// distribute, sublicense, and/or sell copies of the Software, and to permit
-// persons to whom the Software is furnished to do so, subject to the
-// following conditions:
-//
-// The above copyright notice and this permission notice shall be included
-// in all copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
-// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
-// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
-// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
-// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
-// USE OR OTHER DEALINGS IN THE SOFTWARE.
-
-// a transform stream is a readable/writable stream where you do
-// something with the data.  Sometimes it's called a "filter",
-// but that's not a great name for it, since that implies a thing where
-// some bits pass through, and others are simply ignored.  (That would
-// be a valid example of a transform, of course.)
-//
-// While the output is causally related to the input, it's not a
-// necessarily symmetric or synchronous transformation.  For example,
-// a zlib stream might take multiple plain-text writes(), and then
-// emit a single compressed chunk some time in the future.
-//
-// Here's how this works:
-//
-// The Transform stream has all the aspects of the readable and writable
-// stream classes.  When you write(chunk), that calls _write(chunk,cb)
-// internally, and returns false if there's a lot of pending writes
-// buffered up.  When you call read(), that calls _read(n) until
-// there's enough pending readable data buffered up.
-//
-// In a transform stream, the written data is placed in a buffer.  When
-// _read(n) is called, it transforms the queued up data, calling the
-// buffered _write cb's as it consumes chunks.  If consuming a single
-// written chunk would result in multiple output chunks, then the first
-// outputted bit calls the readcb, and subsequent chunks just go into
-// the read buffer, and will cause it to emit 'readable' if necessary.
-//
-// This way, back-pressure is actually determined by the reading side,
-// since _read has to be called to start processing a new chunk.  However,
-// a pathological inflate type of transform can cause excessive buffering
-// here.  For example, imagine a stream where every byte of input is
-// interpreted as an integer from 0-255, and then results in that many
-// bytes of output.  Writing the 4 bytes {ff,ff,ff,ff} would result in
-// 1kb of data being output.  In this case, you could write a very small
-// amount of input, and end up with a very large amount of output.  In
-// such a pathological inflating mechanism, there'd be no way to tell
-// the system to stop doing the transform.  A single 4MB write could
-// cause the system to run out of memory.
-//
-// However, even in such a pathological case, only a single written chunk
-// would be consumed, and then the rest would wait (un-transformed) until
-// the results of the previous transformed chunk were consumed.
-
 'use strict';
 
-module.exports = Transform;
-
-const Duplex = require('_stream_duplex');
-const util = require('util');
-util.inherits(Transform, Duplex);
-
-
-function TransformState(stream) {
-  this.afterTransform = function(er, data) {
-    return afterTransform(stream, er, data);
-  };
-
-  this.needTransform = false;
-  this.transforming = false;
-  this.writecb = null;
-  this.writechunk = null;
-  this.writeencoding = null;
-}
-
-function afterTransform(stream, er, data) {
-  var ts = stream._transformState;
-  ts.transforming = false;
-
-  var cb = ts.writecb;
-
-  if (!cb)
-    return stream.emit('error', new Error('no writecb in Transform class'));
-
-  ts.writechunk = null;
-  ts.writecb = null;
-
-  if (data !== null && data !== undefined)
-    stream.push(data);
-
-  cb(er);
-
-  var rs = stream._readableState;
-  rs.reading = false;
-  if (rs.needReadable || rs.length < rs.highWaterMark) {
-    stream._read(rs.highWaterMark);
-  }
-}
-
-
-function Transform(options) {
-  if (!(this instanceof Transform))
-    return new Transform(options);
-
-  Duplex.call(this, options);
-
-  this._transformState = new TransformState(this);
-
-  var stream = this;
-
-  // start out asking for a readable event once data is transformed.
-  this._readableState.needReadable = true;
-
-  // we have implemented the _read method, and done the other things
-  // that Readable wants before the first _read call, so unset the
-  // sync guard flag.
-  this._readableState.sync = false;
-
-  if (options) {
-    if (typeof options.transform === 'function')
-      this._transform = options.transform;
-
-    if (typeof options.flush === 'function')
-      this._flush = options.flush;
-  }
-
-  // When the writable side finishes, then flush out anything remaining.
-  this.once('prefinish', function() {
-    if (typeof this._flush === 'function')
-      this._flush(function(er, data) {
-        done(stream, er, data);
-      });
-    else
-      done(stream);
-  });
-}
-
-Transform.prototype.push = function(chunk, encoding) {
-  this._transformState.needTransform = false;
-  return Duplex.prototype.push.call(this, chunk, encoding);
-};
-
-// This is the part where you do stuff!
-// override this function in implementation classes.
-// 'chunk' is an input chunk.
-//
-// Call `push(newChunk)` to pass along transformed output
-// to the readable side.  You may call 'push' zero or more times.
-//
-// Call `cb(err)` when you are done with this chunk.  If you pass
-// an error, then that'll put the hurt on the whole operation.  If you
-// never call cb(), then you'll never get another chunk.
-Transform.prototype._transform = function(chunk, encoding, cb) {
-  throw new Error('_transform() is not implemented');
-};
-
-Transform.prototype._write = function(chunk, encoding, cb) {
-  var ts = this._transformState;
-  ts.writecb = cb;
-  ts.writechunk = chunk;
-  ts.writeencoding = encoding;
-  if (!ts.transforming) {
-    var rs = this._readableState;
-    if (ts.needTransform ||
-        rs.needReadable ||
-        rs.length < rs.highWaterMark)
-      this._read(rs.highWaterMark);
-  }
-};
-
-// Doesn't matter what the args are here.
-// _transform does all the work.
-// That we got here means that the readable side wants more data.
-Transform.prototype._read = function(n) {
-  var ts = this._transformState;
-
-  if (ts.writechunk !== null && ts.writecb && !ts.transforming) {
-    ts.transforming = true;
-    this._transform(ts.writechunk, ts.writeencoding, ts.afterTransform);
-  } else {
-    // mark that we need a transform, so that any data that comes in
-    // will get processed, now that we've asked for it.
-    ts.needTransform = true;
-  }
-};
-
-
-function done(stream, er, data) {
-  if (er)
-    return stream.emit('error', er);
-
-  if (data !== null && data !== undefined)
-    stream.push(data);
-
-  // if there's nothing in the write buffer, then that means
-  // that nothing more will ever be provided
-  var ws = stream._writableState;
-  var ts = stream._transformState;
-
-  if (ws.length)
-    throw new Error('Calling transform done when ws.length != 0');
-
-  if (ts.transforming)
-    throw new Error('Calling transform done when still transforming');
+process.emitWarning(`The ${__filename} module is deprecated. Please use stream`,
+                    'DeprecationWarning', 'DEP00XX');
 
-  return stream.push(null);
-}
+module.exports = require('internal/streams/transform');
diff --git a/lib/_stream_writable.js b/lib/_stream_writable.js
index a0a37fbb7a0421..a650351168a388 100644
--- a/lib/_stream_writable.js
+++ b/lib/_stream_writable.js
@@ -1,565 +1,6 @@
-// Copyright Joyent, Inc. and other Node contributors.
-//
-// Permission is hereby granted, free of charge, to any person obtaining a
-// copy of this software and associated documentation files (the
-// "Software"), to deal in the Software without restriction, including
-// without limitation the rights to use, copy, modify, merge, publish,
-// distribute, sublicense, and/or sell copies of the Software, and to permit
-// persons to whom the Software is furnished to do so, subject to the
-// following conditions:
-//
-// The above copyright notice and this permission notice shall be included
-// in all copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
-// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
-// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
-// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
-// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
-// USE OR OTHER DEALINGS IN THE SOFTWARE.
-
-// A bit simpler than readable streams.
-// Implement an async ._write(chunk, encoding, cb), and it'll handle all
-// the drain event emission and buffering.
-
 'use strict';
 
-module.exports = Writable;
-Writable.WritableState = WritableState;
-
-const util = require('util');
-const internalUtil = require('internal/util');
-const Stream = require('stream');
-const Buffer = require('buffer').Buffer;
-
-util.inherits(Writable, Stream);
-
-function nop() {}
-
-function WritableState(options, stream) {
-  options = options || {};
-
-  // object stream flag to indicate whether or not this stream
-  // contains buffers or objects.
-  this.objectMode = !!options.objectMode;
-
-  if (stream instanceof Stream.Duplex)
-    this.objectMode = this.objectMode || !!options.writableObjectMode;
-
-  // the point at which write() starts returning false
-  // Note: 0 is a valid value, means that we always return false if
-  // the entire buffer is not flushed immediately on write()
-  var hwm = options.highWaterMark;
-  var defaultHwm = this.objectMode ? 16 : 16 * 1024;
-  this.highWaterMark = (hwm || hwm === 0) ? hwm : defaultHwm;
-
-  // cast to ints.
-  this.highWaterMark = ~~this.highWaterMark;
-
-  // drain event flag.
-  this.needDrain = false;
-  // at the start of calling end()
-  this.ending = false;
-  // when end() has been called, and returned
-  this.ended = false;
-  // when 'finish' is emitted
-  this.finished = false;
-
-  // should we decode strings into buffers before passing to _write?
-  // this is here so that some node-core streams can optimize string
-  // handling at a lower level.
-  var noDecode = options.decodeStrings === false;
-  this.decodeStrings = !noDecode;
-
-  // Crypto is kind of old and crusty.  Historically, its default string
-  // encoding is 'binary' so we have to make this configurable.
-  // Everything else in the universe uses 'utf8', though.
-  this.defaultEncoding = options.defaultEncoding || 'utf8';
-
-  // not an actual buffer we keep track of, but a measurement
-  // of how much we're waiting to get pushed to some underlying
-  // socket or file.
-  this.length = 0;
-
-  // a flag to see when we're in the middle of a write.
-  this.writing = false;
-
-  // when true all writes will be buffered until .uncork() call
-  this.corked = 0;
-
-  // a flag to be able to tell if the onwrite cb is called immediately,
-  // or on a later tick.  We set this to true at first, because any
-  // actions that shouldn't happen until "later" should generally also
-  // not happen before the first write call.
-  this.sync = true;
-
-  // a flag to know if we're processing previously buffered items, which
-  // may call the _write() callback in the same tick, so that we don't
-  // end up in an overlapped onwrite situation.
-  this.bufferProcessing = false;
-
-  // the callback that's passed to _write(chunk,cb)
-  this.onwrite = onwrite.bind(undefined, stream);
-
-  // the callback that the user supplies to write(chunk,encoding,cb)
-  this.writecb = null;
-
-  // the amount that is being written when _write is called.
-  this.writelen = 0;
-
-  this.bufferedRequest = null;
-  this.lastBufferedRequest = null;
-
-  // number of pending user-supplied write callbacks
-  // this must be 0 before 'finish' can be emitted
-  this.pendingcb = 0;
-
-  // emit prefinish if the only thing we're waiting for is _write cbs
-  // This is relevant for synchronous Transform streams
-  this.prefinished = false;
-
-  // True if the error was already emitted and should not be thrown again
-  this.errorEmitted = false;
-
-  // count buffered requests
-  this.bufferedRequestCount = 0;
-
-  // allocate the first CorkedRequest, there is always
-  // one allocated and free to use, and we maintain at most two
-  var corkReq = { next: null, entry: null, finish: undefined };
-  corkReq.finish = onCorkedFinish.bind(undefined, corkReq, this);
-  this.corkedRequestsFree = corkReq;
-}
-
-WritableState.prototype.getBuffer = function getBuffer() {
-  var current = this.bufferedRequest;
-  var out = [];
-  while (current) {
-    out.push(current);
-    current = current.next;
-  }
-  return out;
-};
-
-Object.defineProperty(WritableState.prototype, 'buffer', {
-  get: internalUtil.deprecate(function() {
-    return this.getBuffer();
-  }, '_writableState.buffer is deprecated. Use _writableState.getBuffer ' +
-     'instead.', 'DEP0003')
-});
-
-// Test _writableState for inheritance to account for Duplex streams,
-// whose prototype chain only points to Readable.
-var realHasInstance;
-if (typeof Symbol === 'function' && Symbol.hasInstance) {
-  realHasInstance = Function.prototype[Symbol.hasInstance];
-  Object.defineProperty(Writable, Symbol.hasInstance, {
-    value: function(object) {
-      if (realHasInstance.call(this, object))
-        return true;
-
-      return object && object._writableState instanceof WritableState;
-    }
-  });
-} else {
-  realHasInstance = function(object) {
-    return object instanceof this;
-  };
-}
-
-function Writable(options) {
-  // Writable ctor is applied to Duplexes, too.
-  // `realHasInstance` is necessary because using plain `instanceof`
-  // would return false, as no `_writableState` property is attached.
-
-  // Trying to use the custom `instanceof` for Writable here will also break the
-  // Node.js LazyTransform implementation, which has a non-trivial getter for
-  // `_writableState` that would lead to infinite recursion.
-  if (!(realHasInstance.call(Writable, this)) &&
-      !(this instanceof Stream.Duplex)) {
-    return new Writable(options);
-  }
-
-  this._writableState = new WritableState(options, this);
-
-  // legacy.
-  this.writable = true;
-
-  if (options) {
-    if (typeof options.write === 'function')
-      this._write = options.write;
-
-    if (typeof options.writev === 'function')
-      this._writev = options.writev;
-  }
-
-  Stream.call(this);
-}
-
-// Otherwise people can pipe Writable streams, which is just wrong.
-Writable.prototype.pipe = function() {
-  this.emit('error', new Error('Cannot pipe, not readable'));
-};
-
-
-function writeAfterEnd(stream, cb) {
-  var er = new Error('write after end');
-  // TODO: defer error events consistently everywhere, not just the cb
-  stream.emit('error', er);
-  process.nextTick(cb, er);
-}
-
-// Checks that a user-supplied chunk is valid, especially for the particular
-// mode the stream is in. Currently this means that `null` is never accepted
-// and undefined/non-string values are only allowed in object mode.
-function validChunk(stream, state, chunk, cb) {
-  var valid = true;
-  var er = false;
-
-  if (chunk === null) {
-    er = new TypeError('May not write null values to stream');
-  } else if (typeof chunk !== 'string' &&
-             chunk !== undefined &&
-             !state.objectMode) {
-    er = new TypeError('Invalid non-string/buffer chunk');
-  }
-  if (er) {
-    stream.emit('error', er);
-    process.nextTick(cb, er);
-    valid = false;
-  }
-  return valid;
-}
-
-Writable.prototype.write = function(chunk, encoding, cb) {
-  var state = this._writableState;
-  var ret = false;
-  var isBuf = (chunk instanceof Buffer);
-
-  if (typeof encoding === 'function') {
-    cb = encoding;
-    encoding = null;
-  }
-
-  if (isBuf)
-    encoding = 'buffer';
-  else if (!encoding)
-    encoding = state.defaultEncoding;
-
-  if (typeof cb !== 'function')
-    cb = nop;
-
-  if (state.ended)
-    writeAfterEnd(this, cb);
-  else if (isBuf || validChunk(this, state, chunk, cb)) {
-    state.pendingcb++;
-    ret = writeOrBuffer(this, state, isBuf, chunk, encoding, cb);
-  }
-
-  return ret;
-};
-
-Writable.prototype.cork = function() {
-  var state = this._writableState;
-
-  state.corked++;
-};
-
-Writable.prototype.uncork = function() {
-  var state = this._writableState;
-
-  if (state.corked) {
-    state.corked--;
-
-    if (!state.writing &&
-        !state.corked &&
-        !state.finished &&
-        !state.bufferProcessing &&
-        state.bufferedRequest)
-      clearBuffer(this, state);
-  }
-};
-
-Writable.prototype.setDefaultEncoding = function setDefaultEncoding(encoding) {
-  // node::ParseEncoding() requires lower case.
-  if (typeof encoding === 'string')
-    encoding = encoding.toLowerCase();
-  if (!Buffer.isEncoding(encoding))
-    throw new TypeError('Unknown encoding: ' + encoding);
-  this._writableState.defaultEncoding = encoding;
-  return this;
-};
-
-function decodeChunk(state, chunk, encoding) {
-  if (!state.objectMode &&
-      state.decodeStrings !== false &&
-      typeof chunk === 'string') {
-    chunk = Buffer.from(chunk, encoding);
-  }
-  return chunk;
-}
-
-// if we're already writing something, then just put this
-// in the queue, and wait our turn.  Otherwise, call _write
-// If we return false, then we need a drain event, so set that flag.
-function writeOrBuffer(stream, state, isBuf, chunk, encoding, cb) {
-  if (!isBuf) {
-    var newChunk = decodeChunk(state, chunk, encoding);
-    if (chunk !== newChunk) {
-      encoding = 'buffer';
-      chunk = newChunk;
-    }
-  }
-  var len = state.objectMode ? 1 : chunk.length;
-
-  state.length += len;
-
-  var ret = state.length < state.highWaterMark;
-  // we must ensure that previous needDrain will not be reset to false.
-  if (!ret)
-    state.needDrain = true;
-
-  if (state.writing || state.corked) {
-    var last = state.lastBufferedRequest;
-    state.lastBufferedRequest = { chunk, encoding, callback: cb, next: null };
-    if (last) {
-      last.next = state.lastBufferedRequest;
-    } else {
-      state.bufferedRequest = state.lastBufferedRequest;
-    }
-    state.bufferedRequestCount += 1;
-  } else {
-    doWrite(stream, state, false, len, chunk, encoding, cb);
-  }
-
-  return ret;
-}
-
-function doWrite(stream, state, writev, len, chunk, encoding, cb) {
-  state.writelen = len;
-  state.writecb = cb;
-  state.writing = true;
-  state.sync = true;
-  if (writev)
-    stream._writev(chunk, state.onwrite);
-  else
-    stream._write(chunk, encoding, state.onwrite);
-  state.sync = false;
-}
-
-function onwriteError(stream, state, sync, er, cb) {
-  --state.pendingcb;
-  if (sync)
-    process.nextTick(cb, er);
-  else
-    cb(er);
-
-  stream._writableState.errorEmitted = true;
-  stream.emit('error', er);
-}
-
-function onwriteStateUpdate(state) {
-  state.writing = false;
-  state.writecb = null;
-  state.length -= state.writelen;
-  state.writelen = 0;
-}
-
-function onwrite(stream, er) {
-  var state = stream._writableState;
-  var sync = state.sync;
-  var cb = state.writecb;
-
-  onwriteStateUpdate(state);
-
-  if (er)
-    onwriteError(stream, state, sync, er, cb);
-  else {
-    // Check if we're actually ready to finish, but don't emit yet
-    var finished = needFinish(state);
-
-    if (!finished &&
-        !state.corked &&
-        !state.bufferProcessing &&
-        state.bufferedRequest) {
-      clearBuffer(stream, state);
-    }
-
-    if (sync) {
-      process.nextTick(afterWrite, stream, state, finished, cb);
-    } else {
-      afterWrite(stream, state, finished, cb);
-    }
-  }
-}
-
-function afterWrite(stream, state, finished, cb) {
-  if (!finished)
-    onwriteDrain(stream, state);
-  state.pendingcb--;
-  cb();
-  finishMaybe(stream, state);
-}
-
-// Must force callback to be called on nextTick, so that we don't
-// emit 'drain' before the write() consumer gets the 'false' return
-// value, and has a chance to attach a 'drain' listener.
-function onwriteDrain(stream, state) {
-  if (state.length === 0 && state.needDrain) {
-    state.needDrain = false;
-    stream.emit('drain');
-  }
-}
-
-// if there's something in the buffer waiting, then process it
-function clearBuffer(stream, state) {
-  state.bufferProcessing = true;
-  var entry = state.bufferedRequest;
-
-  if (stream._writev && entry && entry.next) {
-    // Fast case, write everything using _writev()
-    var l = state.bufferedRequestCount;
-    var buffer = new Array(l);
-    var holder = state.corkedRequestsFree;
-    holder.entry = entry;
-
-    var count = 0;
-    while (entry) {
-      buffer[count] = entry;
-      entry = entry.next;
-      count += 1;
-    }
-
-    doWrite(stream, state, true, state.length, buffer, '', holder.finish);
-
-    // doWrite is almost always async, defer these to save a bit of time
-    // as the hot path ends with doWrite
-    state.pendingcb++;
-    state.lastBufferedRequest = null;
-    if (holder.next) {
-      state.corkedRequestsFree = holder.next;
-      holder.next = null;
-    } else {
-      var corkReq = { next: null, entry: null, finish: undefined };
-      corkReq.finish = onCorkedFinish.bind(undefined, corkReq, state);
-      state.corkedRequestsFree = corkReq;
-    }
-  } else {
-    // Slow case, write chunks one-by-one
-    while (entry) {
-      var chunk = entry.chunk;
-      var encoding = entry.encoding;
-      var cb = entry.callback;
-      var len = state.objectMode ? 1 : chunk.length;
-
-      doWrite(stream, state, false, len, chunk, encoding, cb);
-      entry = entry.next;
-      // if we didn't call the onwrite immediately, then
-      // it means that we need to wait until it does.
-      // also, that means that the chunk and cb are currently
-      // being processed, so move the buffer counter past them.
-      if (state.writing) {
-        break;
-      }
-    }
-
-    if (entry === null)
-      state.lastBufferedRequest = null;
-  }
-
-  state.bufferedRequestCount = 0;
-  state.bufferedRequest = entry;
-  state.bufferProcessing = false;
-}
-
-Writable.prototype._write = function(chunk, encoding, cb) {
-  cb(new Error('_write() is not implemented'));
-};
-
-Writable.prototype._writev = null;
-
-Writable.prototype.end = function(chunk, encoding, cb) {
-  var state = this._writableState;
-
-  if (typeof chunk === 'function') {
-    cb = chunk;
-    chunk = null;
-    encoding = null;
-  } else if (typeof encoding === 'function') {
-    cb = encoding;
-    encoding = null;
-  }
-
-  if (chunk !== null && chunk !== undefined)
-    this.write(chunk, encoding);
-
-  // .end() fully uncorks
-  if (state.corked) {
-    state.corked = 1;
-    this.uncork();
-  }
-
-  // ignore unnecessary end() calls.
-  if (!state.ending && !state.finished)
-    endWritable(this, state, cb);
-};
-
-
-function needFinish(state) {
-  return (state.ending &&
-          state.length === 0 &&
-          state.bufferedRequest === null &&
-          !state.finished &&
-          !state.writing);
-}
-
-function prefinish(stream, state) {
-  if (!state.prefinished) {
-    state.prefinished = true;
-    stream.emit('prefinish');
-  }
-}
-
-function finishMaybe(stream, state) {
-  var need = needFinish(state);
-  if (need) {
-    if (state.pendingcb === 0) {
-      prefinish(stream, state);
-      state.finished = true;
-      stream.emit('finish');
-    } else {
-      prefinish(stream, state);
-    }
-  }
-  return need;
-}
-
-function endWritable(stream, state, cb) {
-  state.ending = true;
-  finishMaybe(stream, state);
-  if (cb) {
-    if (state.finished)
-      process.nextTick(cb);
-    else
-      stream.once('finish', cb);
-  }
-  state.ended = true;
-  stream.writable = false;
-}
+process.emitWarning(`The ${__filename} module is deprecated. Please use stream`,
+                    'DeprecationWarning', 'DEP00XX');
 
-function onCorkedFinish(corkReq, state, err) {
-  var entry = corkReq.entry;
-  corkReq.entry = null;
-  while (entry) {
-    var cb = entry.callback;
-    state.pendingcb--;
-    cb(err);
-    entry = entry.next;
-  }
-  if (state.corkedRequestsFree) {
-    state.corkedRequestsFree.next = corkReq;
-  } else {
-    state.corkedRequestsFree = corkReq;
-  }
-}
+module.exports = require('internal/streams/writable');
diff --git a/lib/internal/streams/duplex.js b/lib/internal/streams/duplex.js
new file mode 100644
index 00000000000000..168cb34d8215cf
--- /dev/null
+++ b/lib/internal/streams/duplex.js
@@ -0,0 +1,78 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+// a duplex stream is just a stream that is both readable and writable.
+// Since JS doesn't have multiple prototypal inheritance, this class
+// prototypally inherits from Readable, and then parasitically from
+// Writable.
+
+'use strict';
+
+module.exports = Duplex;
+
+const util = require('util');
+const Readable = require('internal/streams/readable');
+const Writable = require('internal/streams/writable');
+
+util.inherits(Duplex, Readable);
+
+var keys = Object.keys(Writable.prototype);
+for (var v = 0; v < keys.length; v++) {
+  var method = keys[v];
+  if (!Duplex.prototype[method])
+    Duplex.prototype[method] = Writable.prototype[method];
+}
+
+function Duplex(options) {
+  if (!(this instanceof Duplex))
+    return new Duplex(options);
+
+  Readable.call(this, options);
+  Writable.call(this, options);
+
+  if (options && options.readable === false)
+    this.readable = false;
+
+  if (options && options.writable === false)
+    this.writable = false;
+
+  this.allowHalfOpen = true;
+  if (options && options.allowHalfOpen === false)
+    this.allowHalfOpen = false;
+
+  this.once('end', onend);
+}
+
+// the no-half-open enforcer
+function onend() {
+  // if we allow half-open state, or if the writable side ended,
+  // then we're ok.
+  if (this.allowHalfOpen || this._writableState.ended)
+    return;
+
+  // no more data can be written.
+  // But allow more writes to happen in this tick.
+  process.nextTick(onEndNT, this);
+}
+
+function onEndNT(self) {
+  self.end();
+}
diff --git a/lib/internal/streams/passthrough.js b/lib/internal/streams/passthrough.js
new file mode 100644
index 00000000000000..9bdf86ef76af3e
--- /dev/null
+++ b/lib/internal/streams/passthrough.js
@@ -0,0 +1,43 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+// a passthrough stream.
+// basically just the most minimal sort of Transform stream.
+// Every written chunk gets output as-is.
+
+'use strict';
+
+module.exports = PassThrough;
+
+const Transform = require('internal/streams/transform');
+const util = require('util');
+util.inherits(PassThrough, Transform);
+
+function PassThrough(options) {
+  if (!(this instanceof PassThrough))
+    return new PassThrough(options);
+
+  Transform.call(this, options);
+}
+
+PassThrough.prototype._transform = function(chunk, encoding, cb) {
+  cb(null, chunk);
+};
diff --git a/lib/internal/streams/readable.js b/lib/internal/streams/readable.js
new file mode 100644
index 00000000000000..879e5ddb53fe40
--- /dev/null
+++ b/lib/internal/streams/readable.js
@@ -0,0 +1,994 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+'use strict';
+
+module.exports = Readable;
+Readable.ReadableState = ReadableState;
+
+const EE = require('events');
+const Stream = require('stream');
+const Buffer = require('buffer').Buffer;
+const util = require('util');
+const debug = util.debuglog('stream');
+const BufferList = require('internal/streams/BufferList');
+var StringDecoder;
+
+util.inherits(Readable, Stream);
+
+const kProxyEvents = ['error', 'close', 'destroy', 'pause', 'resume'];
+
+function prependListener(emitter, event, fn) {
+  // Sadly this is not cacheable as some libraries bundle their own
+  // event emitter implementation with them.
+  if (typeof emitter.prependListener === 'function') {
+    return emitter.prependListener(event, fn);
+  } else {
+    // This is a hack to make sure that our error handler is attached before any
+    // userland ones.  NEVER DO THIS. This is here only because this code needs
+    // to continue to work with older versions of Node.js that do not include
+    // the prependListener() method. The goal is to eventually remove this hack.
+    if (!emitter._events || !emitter._events[event])
+      emitter.on(event, fn);
+    else if (Array.isArray(emitter._events[event]))
+      emitter._events[event].unshift(fn);
+    else
+      emitter._events[event] = [fn, emitter._events[event]];
+  }
+}
+
+function ReadableState(options, stream) {
+  options = options || {};
+
+  // object stream flag. Used to make read(n) ignore n and to
+  // make all the buffer merging and length checks go away
+  this.objectMode = !!options.objectMode;
+
+  if (stream instanceof Stream.Duplex)
+    this.objectMode = this.objectMode || !!options.readableObjectMode;
+
+  // the point at which it stops calling _read() to fill the buffer
+  // Note: 0 is a valid value, means "don't call _read preemptively ever"
+  var hwm = options.highWaterMark;
+  var defaultHwm = this.objectMode ? 16 : 16 * 1024;
+  this.highWaterMark = (hwm || hwm === 0) ? hwm : defaultHwm;
+
+  // cast to ints.
+  this.highWaterMark = ~~this.highWaterMark;
+
+  // A linked list is used to store data chunks instead of an array because the
+  // linked list can remove elements from the beginning faster than
+  // array.shift()
+  this.buffer = new BufferList();
+  this.length = 0;
+  this.pipes = null;
+  this.pipesCount = 0;
+  this.flowing = null;
+  this.ended = false;
+  this.endEmitted = false;
+  this.reading = false;
+
+  // a flag to be able to tell if the event 'readable'/'data' is emitted
+  // immediately, or on a later tick.  We set this to true at first, because
+  // any actions that shouldn't happen until "later" should generally also
+  // not happen before the first read call.
+  this.sync = true;
+
+  // whenever we return null, then we set a flag to say
+  // that we're awaiting a 'readable' event emission.
+  this.needReadable = false;
+  this.emittedReadable = false;
+  this.readableListening = false;
+  this.resumeScheduled = false;
+
+  // Crypto is kind of old and crusty.  Historically, its default string
+  // encoding is 'binary' so we have to make this configurable.
+  // Everything else in the universe uses 'utf8', though.
+  this.defaultEncoding = options.defaultEncoding || 'utf8';
+
+  // the number of writers that are awaiting a drain event in .pipe()s
+  this.awaitDrain = 0;
+
+  // if true, a maybeReadMore has been scheduled
+  this.readingMore = false;
+
+  this.decoder = null;
+  this.encoding = null;
+  if (options.encoding) {
+    if (!StringDecoder)
+      StringDecoder = require('string_decoder').StringDecoder;
+    this.decoder = new StringDecoder(options.encoding);
+    this.encoding = options.encoding;
+  }
+}
+
+function Readable(options) {
+  if (!(this instanceof Readable))
+    return new Readable(options);
+
+  this._readableState = new ReadableState(options, this);
+
+  // legacy
+  this.readable = true;
+
+  if (options && typeof options.read === 'function')
+    this._read = options.read;
+
+  Stream.call(this);
+}
+
+// Manually shove something into the read() buffer.
+// This returns true if the highWaterMark has not been hit yet,
+// similar to how Writable.write() returns true if you should
+// write() some more.
+Readable.prototype.push = function(chunk, encoding) {
+  var state = this._readableState;
+
+  if (!state.objectMode && typeof chunk === 'string') {
+    encoding = encoding || state.defaultEncoding;
+    if (encoding !== state.encoding) {
+      chunk = Buffer.from(chunk, encoding);
+      encoding = '';
+    }
+  }
+
+  return readableAddChunk(this, state, chunk, encoding, false);
+};
+
+// Unshift should *always* be something directly out of read()
+Readable.prototype.unshift = function(chunk) {
+  var state = this._readableState;
+  return readableAddChunk(this, state, chunk, '', true);
+};
+
+Readable.prototype.isPaused = function() {
+  return this._readableState.flowing === false;
+};
+
+function readableAddChunk(stream, state, chunk, encoding, addToFront) {
+  var er = chunkInvalid(state, chunk);
+  if (er) {
+    stream.emit('error', er);
+  } else if (chunk === null) {
+    state.reading = false;
+    onEofChunk(stream, state);
+  } else if (state.objectMode || chunk && chunk.length > 0) {
+    if (state.ended && !addToFront) {
+      const e = new Error('stream.push() after EOF');
+      stream.emit('error', e);
+    } else if (state.endEmitted && addToFront) {
+      const e = new Error('stream.unshift() after end event');
+      stream.emit('error', e);
+    } else {
+      var skipAdd;
+      if (state.decoder && !addToFront && !encoding) {
+        chunk = state.decoder.write(chunk);
+        skipAdd = (!state.objectMode && chunk.length === 0);
+      }
+
+      if (!addToFront)
+        state.reading = false;
+
+      // Don't add to the buffer if we've decoded to an empty string chunk and
+      // we're not in object mode
+      if (!skipAdd) {
+        // if we want the data now, just emit it.
+        if (state.flowing && state.length === 0 && !state.sync) {
+          stream.emit('data', chunk);
+          stream.read(0);
+        } else {
+          // update the buffer info.
+          state.length += state.objectMode ? 1 : chunk.length;
+          if (addToFront)
+            state.buffer.unshift(chunk);
+          else
+            state.buffer.push(chunk);
+
+          if (state.needReadable)
+            emitReadable(stream);
+        }
+      }
+
+      maybeReadMore(stream, state);
+    }
+  } else if (!addToFront) {
+    state.reading = false;
+  }
+
+  return needMoreData(state);
+}
+
+
+// if it's past the high water mark, we can push in some more.
+// Also, if we have no data yet, we can stand some
+// more bytes.  This is to work around cases where hwm=0,
+// such as the repl.  Also, if the push() triggered a
+// readable event, and the user called read(largeNumber) such that
+// needReadable was set, then we ought to push more, so that another
+// 'readable' event will be triggered.
+function needMoreData(state) {
+  return !state.ended &&
+         (state.needReadable ||
+          state.length < state.highWaterMark ||
+          state.length === 0);
+}
+
+// backwards compatibility.
+Readable.prototype.setEncoding = function(enc) {
+  if (!StringDecoder)
+    StringDecoder = require('string_decoder').StringDecoder;
+  this._readableState.decoder = new StringDecoder(enc);
+  this._readableState.encoding = enc;
+  return this;
+};
+
+// Don't raise the hwm > 8MB
+const MAX_HWM = 0x800000;
+function computeNewHighWaterMark(n) {
+  if (n >= MAX_HWM) {
+    n = MAX_HWM;
+  } else {
+    // Get the next highest power of 2 to prevent increasing hwm excessively in
+    // tiny amounts
+    n--;
+    n |= n >>> 1;
+    n |= n >>> 2;
+    n |= n >>> 4;
+    n |= n >>> 8;
+    n |= n >>> 16;
+    n++;
+  }
+  return n;
+}
+
+// This function is designed to be inlinable, so please take care when making
+// changes to the function body.
+function howMuchToRead(n, state) {
+  if (n <= 0 || (state.length === 0 && state.ended))
+    return 0;
+  if (state.objectMode)
+    return 1;
+  if (n !== n) {
+    // Only flow one buffer at a time
+    if (state.flowing && state.length)
+      return state.buffer.head.data.length;
+    else
+      return state.length;
+  }
+  // If we're asking for more than the current hwm, then raise the hwm.
+  if (n > state.highWaterMark)
+    state.highWaterMark = computeNewHighWaterMark(n);
+  if (n <= state.length)
+    return n;
+  // Don't have enough
+  if (!state.ended) {
+    state.needReadable = true;
+    return 0;
+  }
+  return state.length;
+}
+
+// you can override either this method, or the async _read(n) below.
+Readable.prototype.read = function(n) {
+  debug('read', n);
+  n = parseInt(n, 10);
+  var state = this._readableState;
+  var nOrig = n;
+
+  if (n !== 0)
+    state.emittedReadable = false;
+
+  // if we're doing read(0) to trigger a readable event, but we
+  // already have a bunch of data in the buffer, then just trigger
+  // the 'readable' event and move on.
+  if (n === 0 &&
+      state.needReadable &&
+      (state.length >= state.highWaterMark || state.ended)) {
+    debug('read: emitReadable', state.length, state.ended);
+    if (state.length === 0 && state.ended)
+      endReadable(this);
+    else
+      emitReadable(this);
+    return null;
+  }
+
+  n = howMuchToRead(n, state);
+
+  // if we've ended, and we're now clear, then finish it up.
+  if (n === 0 && state.ended) {
+    if (state.length === 0)
+      endReadable(this);
+    return null;
+  }
+
+  // All the actual chunk generation logic needs to be
+  // *below* the call to _read.  The reason is that in certain
+  // synthetic stream cases, such as passthrough streams, _read
+  // may be a completely synchronous operation which may change
+  // the state of the read buffer, providing enough data when
+  // before there was *not* enough.
+  //
+  // So, the steps are:
+  // 1. Figure out what the state of things will be after we do
+  // a read from the buffer.
+  //
+  // 2. If that resulting state will trigger a _read, then call _read.
+  // Note that this may be asynchronous, or synchronous.  Yes, it is
+  // deeply ugly to write APIs this way, but that still doesn't mean
+  // that the Readable class should behave improperly, as streams are
+  // designed to be sync/async agnostic.
+  // Take note if the _read call is sync or async (ie, if the read call
+  // has returned yet), so that we know whether or not it's safe to emit
+  // 'readable' etc.
+  //
+  // 3. Actually pull the requested chunks out of the buffer and return.
+
+  // if we need a readable event, then we need to do some reading.
+  var doRead = state.needReadable;
+  debug('need readable', doRead);
+
+  // if we currently have less than the highWaterMark, then also read some
+  if (state.length === 0 || state.length - n < state.highWaterMark) {
+    doRead = true;
+    debug('length less than watermark', doRead);
+  }
+
+  // however, if we've ended, then there's no point, and if we're already
+  // reading, then it's unnecessary.
+  if (state.ended || state.reading) {
+    doRead = false;
+    debug('reading or ended', doRead);
+  } else if (doRead) {
+    debug('do read');
+    state.reading = true;
+    state.sync = true;
+    // if the length is currently zero, then we *need* a readable event.
+    if (state.length === 0)
+      state.needReadable = true;
+    // call internal read method
+    this._read(state.highWaterMark);
+    state.sync = false;
+    // If _read pushed data synchronously, then `reading` will be false,
+    // and we need to re-evaluate how much data we can return to the user.
+    if (!state.reading)
+      n = howMuchToRead(nOrig, state);
+  }
+
+  var ret;
+  if (n > 0)
+    ret = fromList(n, state);
+  else
+    ret = null;
+
+  if (ret === null) {
+    state.needReadable = true;
+    n = 0;
+  } else {
+    state.length -= n;
+  }
+
+  if (state.length === 0) {
+    // If we have nothing in the buffer, then we want to know
+    // as soon as we *do* get something into the buffer.
+    if (!state.ended)
+      state.needReadable = true;
+
+    // If we tried to read() past the EOF, then emit end on the next tick.
+    if (nOrig !== n && state.ended)
+      endReadable(this);
+  }
+
+  if (ret !== null)
+    this.emit('data', ret);
+
+  return ret;
+};
+
+function chunkInvalid(state, chunk) {
+  var er = null;
+  if (!(chunk instanceof Buffer) &&
+      typeof chunk !== 'string' &&
+      chunk !== null &&
+      chunk !== undefined &&
+      !state.objectMode) {
+    er = new TypeError('Invalid non-string/buffer chunk');
+  }
+  return er;
+}
+
+
+function onEofChunk(stream, state) {
+  if (state.ended) return;
+  if (state.decoder) {
+    var chunk = state.decoder.end();
+    if (chunk && chunk.length) {
+      state.buffer.push(chunk);
+      state.length += state.objectMode ? 1 : chunk.length;
+    }
+  }
+  state.ended = true;
+
+  // emit 'readable' now to make sure it gets picked up.
+  emitReadable(stream);
+}
+
+// Don't emit readable right away in sync mode, because this can trigger
+// another read() call => stack overflow.  This way, it might trigger
+// a nextTick recursion warning, but that's not so bad.
+function emitReadable(stream) {
+  var state = stream._readableState;
+  state.needReadable = false;
+  if (!state.emittedReadable) {
+    debug('emitReadable', state.flowing);
+    state.emittedReadable = true;
+    if (state.sync)
+      process.nextTick(emitReadable_, stream);
+    else
+      emitReadable_(stream);
+  }
+}
+
+function emitReadable_(stream) {
+  debug('emit readable');
+  stream.emit('readable');
+  flow(stream);
+}
+
+
+// at this point, the user has presumably seen the 'readable' event,
+// and called read() to consume some data.  that may have triggered
+// in turn another _read(n) call, in which case reading = true if
+// it's in progress.
+// However, if we're not ended, or reading, and the length < hwm,
+// then go ahead and try to read some more preemptively.
+function maybeReadMore(stream, state) {
+  if (!state.readingMore) {
+    state.readingMore = true;
+    process.nextTick(maybeReadMore_, stream, state);
+  }
+}
+
+function maybeReadMore_(stream, state) {
+  var len = state.length;
+  while (!state.reading && !state.flowing && !state.ended &&
+         state.length < state.highWaterMark) {
+    debug('maybeReadMore read 0');
+    stream.read(0);
+    if (len === state.length)
+      // didn't get any data, stop spinning.
+      break;
+    else
+      len = state.length;
+  }
+  state.readingMore = false;
+}
+
+// abstract method.  to be overridden in specific implementation classes.
+// call cb(er, data) where data is <= n in length.
+// for virtual (non-string, non-buffer) streams, "length" is somewhat
+// arbitrary, and perhaps not very meaningful.
+Readable.prototype._read = function(n) {
+  this.emit('error', new Error('_read() is not implemented'));
+};
+
+Readable.prototype.pipe = function(dest, pipeOpts) {
+  var src = this;
+  var state = this._readableState;
+
+  switch (state.pipesCount) {
+    case 0:
+      state.pipes = dest;
+      break;
+    case 1:
+      state.pipes = [state.pipes, dest];
+      break;
+    default:
+      state.pipes.push(dest);
+      break;
+  }
+  state.pipesCount += 1;
+  debug('pipe count=%d opts=%j', state.pipesCount, pipeOpts);
+
+  var doEnd = (!pipeOpts || pipeOpts.end !== false) &&
+              dest !== process.stdout &&
+              dest !== process.stderr;
+
+  var endFn = doEnd ? onend : unpipe;
+  if (state.endEmitted)
+    process.nextTick(endFn);
+  else
+    src.once('end', endFn);
+
+  dest.on('unpipe', onunpipe);
+  function onunpipe(readable) {
+    debug('onunpipe');
+    if (readable === src) {
+      cleanup();
+    }
+  }
+
+  function onend() {
+    debug('onend');
+    dest.end();
+  }
+
+  // when the dest drains, it reduces the awaitDrain counter
+  // on the source.  This would be more elegant with a .once()
+  // handler in flow(), but adding and removing repeatedly is
+  // too slow.
+  var ondrain = pipeOnDrain(src);
+  dest.on('drain', ondrain);
+
+  var cleanedUp = false;
+  function cleanup() {
+    debug('cleanup');
+    // cleanup event handlers once the pipe is broken
+    dest.removeListener('close', onclose);
+    dest.removeListener('finish', onfinish);
+    dest.removeListener('drain', ondrain);
+    dest.removeListener('error', onerror);
+    dest.removeListener('unpipe', onunpipe);
+    src.removeListener('end', onend);
+    src.removeListener('end', unpipe);
+    src.removeListener('data', ondata);
+
+    cleanedUp = true;
+
+    // if the reader is waiting for a drain event from this
+    // specific writer, then it would cause it to never start
+    // flowing again.
+    // So, if this is awaiting a drain, then we just call it now.
+    // If we don't know, then assume that we are waiting for one.
+    if (state.awaitDrain &&
+        (!dest._writableState || dest._writableState.needDrain))
+      ondrain();
+  }
+
+  // If the user pushes more data while we're writing to dest then we'll end up
+  // in ondata again. However, we only want to increase awaitDrain once because
+  // dest will only emit one 'drain' event for the multiple writes.
+  // => Introduce a guard on increasing awaitDrain.
+  var increasedAwaitDrain = false;
+  src.on('data', ondata);
+  function ondata(chunk) {
+    debug('ondata');
+    increasedAwaitDrain = false;
+    var ret = dest.write(chunk);
+    if (false === ret && !increasedAwaitDrain) {
+      // If the user unpiped during `dest.write()`, it is possible
+      // to get stuck in a permanently paused state if that write
+      // also returned false.
+      // => Check whether `dest` is still a piping destination.
+      if (((state.pipesCount === 1 && state.pipes === dest) ||
+           (state.pipesCount > 1 && state.pipes.indexOf(dest) !== -1)) &&
+          !cleanedUp) {
+        debug('false write response, pause', src._readableState.awaitDrain);
+        src._readableState.awaitDrain++;
+        increasedAwaitDrain = true;
+      }
+      src.pause();
+    }
+  }
+
+  // if the dest has an error, then stop piping into it.
+  // however, don't suppress the throwing behavior for this.
+  function onerror(er) {
+    debug('onerror', er);
+    unpipe();
+    dest.removeListener('error', onerror);
+    if (EE.listenerCount(dest, 'error') === 0)
+      dest.emit('error', er);
+  }
+
+  // Make sure our error handler is attached before userland ones.
+  prependListener(dest, 'error', onerror);
+
+  // Both close and finish should trigger unpipe, but only once.
+  function onclose() {
+    dest.removeListener('finish', onfinish);
+    unpipe();
+  }
+  dest.once('close', onclose);
+  function onfinish() {
+    debug('onfinish');
+    dest.removeListener('close', onclose);
+    unpipe();
+  }
+  dest.once('finish', onfinish);
+
+  function unpipe() {
+    debug('unpipe');
+    src.unpipe(dest);
+  }
+
+  // tell the dest that it's being piped to
+  dest.emit('pipe', src);
+
+  // start the flow if it hasn't been started already.
+  if (!state.flowing) {
+    debug('pipe resume');
+    src.resume();
+  }
+
+  return dest;
+};
+
+function pipeOnDrain(src) {
+  return function() {
+    var state = src._readableState;
+    debug('pipeOnDrain', state.awaitDrain);
+    if (state.awaitDrain)
+      state.awaitDrain--;
+    if (state.awaitDrain === 0 && EE.listenerCount(src, 'data')) {
+      state.flowing = true;
+      flow(src);
+    }
+  };
+}
+
+
+Readable.prototype.unpipe = function(dest) {
+  var state = this._readableState;
+
+  // if we're not piping anywhere, then do nothing.
+  if (state.pipesCount === 0)
+    return this;
+
+  // just one destination.  most common case.
+  if (state.pipesCount === 1) {
+    // passed in one, but it's not the right one.
+    if (dest && dest !== state.pipes)
+      return this;
+
+    if (!dest)
+      dest = state.pipes;
+
+    // got a match.
+    state.pipes = null;
+    state.pipesCount = 0;
+    state.flowing = false;
+    if (dest)
+      dest.emit('unpipe', this);
+    return this;
+  }
+
+  // slow case. multiple pipe destinations.
+
+  if (!dest) {
+    // remove all.
+    var dests = state.pipes;
+    var len = state.pipesCount;
+    state.pipes = null;
+    state.pipesCount = 0;
+    state.flowing = false;
+
+    for (var i = 0; i < len; i++)
+      dests[i].emit('unpipe', this);
+    return this;
+  }
+
+  // try to find the right one.
+  var index = state.pipes.indexOf(dest);
+  if (index === -1)
+    return this;
+
+  state.pipes.splice(index, 1);
+  state.pipesCount -= 1;
+  if (state.pipesCount === 1)
+    state.pipes = state.pipes[0];
+
+  dest.emit('unpipe', this);
+
+  return this;
+};
+
+// set up data events if they are asked for
+// Ensure readable listeners eventually get something
+Readable.prototype.on = function(ev, fn) {
+  const res = Stream.prototype.on.call(this, ev, fn);
+
+  if (ev === 'data') {
+    // Start flowing on next tick if stream isn't explicitly paused
+    if (this._readableState.flowing !== false)
+      this.resume();
+  } else if (ev === 'readable') {
+    const state = this._readableState;
+    if (!state.endEmitted && !state.readableListening) {
+      state.readableListening = state.needReadable = true;
+      state.emittedReadable = false;
+      if (!state.reading) {
+        process.nextTick(nReadingNextTick, this);
+      } else if (state.length) {
+        emitReadable(this, state);
+      }
+    }
+  }
+
+  return res;
+};
+Readable.prototype.addListener = Readable.prototype.on;
+
+function nReadingNextTick(self) {
+  debug('readable nexttick read 0');
+  self.read(0);
+}
+
+// pause() and resume() are remnants of the legacy readable stream API
+// If the user uses them, then switch into old mode.
+Readable.prototype.resume = function() {
+  var state = this._readableState;
+  if (!state.flowing) {
+    debug('resume');
+    state.flowing = true;
+    resume(this, state);
+  }
+  return this;
+};
+
+function resume(stream, state) {
+  if (!state.resumeScheduled) {
+    state.resumeScheduled = true;
+    process.nextTick(resume_, stream, state);
+  }
+}
+
+function resume_(stream, state) {
+  if (!state.reading) {
+    debug('resume read 0');
+    stream.read(0);
+  }
+
+  state.resumeScheduled = false;
+  state.awaitDrain = 0;
+  stream.emit('resume');
+  flow(stream);
+  if (state.flowing && !state.reading)
+    stream.read(0);
+}
+
+Readable.prototype.pause = function() {
+  debug('call pause flowing=%j', this._readableState.flowing);
+  if (false !== this._readableState.flowing) {
+    debug('pause');
+    this._readableState.flowing = false;
+    this.emit('pause');
+  }
+  return this;
+};
+
+function flow(stream) {
+  const state = stream._readableState;
+  debug('flow', state.flowing);
+  while (state.flowing && stream.read() !== null);
+}
+
+// wrap an old-style stream as the async data source.
+// This is *not* part of the readable stream interface.
+// It is an ugly unfortunate mess of history.
+Readable.prototype.wrap = function(stream) {
+  var state = this._readableState;
+  var paused = false;
+
+  var self = this;
+  stream.on('end', function() {
+    debug('wrapped end');
+    if (state.decoder && !state.ended) {
+      var chunk = state.decoder.end();
+      if (chunk && chunk.length)
+        self.push(chunk);
+    }
+
+    self.push(null);
+  });
+
+  stream.on('data', function(chunk) {
+    debug('wrapped data');
+    if (state.decoder)
+      chunk = state.decoder.write(chunk);
+
+    // don't skip over falsy values in objectMode
+    if (state.objectMode && (chunk === null || chunk === undefined))
+      return;
+    else if (!state.objectMode && (!chunk || !chunk.length))
+      return;
+
+    var ret = self.push(chunk);
+    if (!ret) {
+      paused = true;
+      stream.pause();
+    }
+  });
+
+  // proxy all the other methods.
+  // important when wrapping filters and duplexes.
+  for (var i in stream) {
+    if (this[i] === undefined && typeof stream[i] === 'function') {
+      this[i] = function(method) {
+        return function() {
+          return stream[method].apply(stream, arguments);
+        };
+      }(i);
+    }
+  }
+
+  // proxy certain important events.
+  for (var n = 0; n < kProxyEvents.length; n++) {
+    stream.on(kProxyEvents[n], self.emit.bind(self, kProxyEvents[n]));
+  }
+
+  // when we try to consume some more bytes, simply unpause the
+  // underlying stream.
+  self._read = function(n) {
+    debug('wrapped _read', n);
+    if (paused) {
+      paused = false;
+      stream.resume();
+    }
+  };
+
+  return self;
+};
+
+
+// exposed for testing purposes only.
+Readable._fromList = fromList;
+
+// Pluck off n bytes from an array of buffers.
+// Length is the combined lengths of all the buffers in the list.
+// This function is designed to be inlinable, so please take care when making
+// changes to the function body.
+function fromList(n, state) {
+  // nothing buffered
+  if (state.length === 0)
+    return null;
+
+  var ret;
+  if (state.objectMode)
+    ret = state.buffer.shift();
+  else if (!n || n >= state.length) {
+    // read it all, truncate the list
+    if (state.decoder)
+      ret = state.buffer.join('');
+    else if (state.buffer.length === 1)
+      ret = state.buffer.head.data;
+    else
+      ret = state.buffer.concat(state.length);
+    state.buffer.clear();
+  } else {
+    // read part of list
+    ret = fromListPartial(n, state.buffer, state.decoder);
+  }
+
+  return ret;
+}
+
+// Extracts only enough buffered data to satisfy the amount requested.
+// This function is designed to be inlinable, so please take care when making
+// changes to the function body.
+function fromListPartial(n, list, hasStrings) {
+  var ret;
+  if (n < list.head.data.length) {
+    // slice is the same for buffers and strings
+    ret = list.head.data.slice(0, n);
+    list.head.data = list.head.data.slice(n);
+  } else if (n === list.head.data.length) {
+    // first chunk is a perfect match
+    ret = list.shift();
+  } else {
+    // result spans more than one buffer
+    ret = (hasStrings ?
+           copyFromBufferString(n, list) :
+           copyFromBuffer(n, list));
+  }
+  return ret;
+}
+
+// Copies a specified amount of characters from the list of buffered data
+// chunks.
+// This function is designed to be inlinable, so please take care when making
+// changes to the function body.
+function copyFromBufferString(n, list) {
+  var p = list.head;
+  var c = 1;
+  var ret = p.data;
+  n -= ret.length;
+  while (p = p.next) {
+    const str = p.data;
+    const nb = (n > str.length ? str.length : n);
+    if (nb === str.length)
+      ret += str;
+    else
+      ret += str.slice(0, n);
+    n -= nb;
+    if (n === 0) {
+      if (nb === str.length) {
+        ++c;
+        if (p.next)
+          list.head = p.next;
+        else
+          list.head = list.tail = null;
+      } else {
+        list.head = p;
+        p.data = str.slice(nb);
+      }
+      break;
+    }
+    ++c;
+  }
+  list.length -= c;
+  return ret;
+}
+
+// Copies a specified amount of bytes from the list of buffered data chunks.
+// This function is designed to be inlinable, so please take care when making
+// changes to the function body.
+function copyFromBuffer(n, list) {
+  const ret = Buffer.allocUnsafe(n);
+  var p = list.head;
+  var c = 1;
+  p.data.copy(ret);
+  n -= p.data.length;
+  while (p = p.next) {
+    const buf = p.data;
+    const nb = (n > buf.length ? buf.length : n);
+    buf.copy(ret, ret.length - n, 0, nb);
+    n -= nb;
+    if (n === 0) {
+      if (nb === buf.length) {
+        ++c;
+        if (p.next)
+          list.head = p.next;
+        else
+          list.head = list.tail = null;
+      } else {
+        list.head = p;
+        p.data = buf.slice(nb);
+      }
+      break;
+    }
+    ++c;
+  }
+  list.length -= c;
+  return ret;
+}
+
+function endReadable(stream) {
+  var state = stream._readableState;
+
+  // If we get here before consuming all the bytes, then that is a
+  // bug in node.  Should never happen.
+  if (state.length > 0)
+    throw new Error('"endReadable()" called on non-empty stream');
+
+  if (!state.endEmitted) {
+    state.ended = true;
+    process.nextTick(endReadableNT, state, stream);
+  }
+}
+
+function endReadableNT(state, stream) {
+  // Check that we didn't get one last unshift.
+  if (!state.endEmitted && state.length === 0) {
+    state.endEmitted = true;
+    stream.readable = false;
+    stream.emit('end');
+  }
+}
diff --git a/lib/internal/streams/transform.js b/lib/internal/streams/transform.js
new file mode 100644
index 00000000000000..6700a77efe584d
--- /dev/null
+++ b/lib/internal/streams/transform.js
@@ -0,0 +1,216 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+// a transform stream is a readable/writable stream where you do
+// something with the data.  Sometimes it's called a "filter",
+// but that's not a great name for it, since that implies a thing where
+// some bits pass through, and others are simply ignored.  (That would
+// be a valid example of a transform, of course.)
+//
+// While the output is causally related to the input, it's not a
+// necessarily symmetric or synchronous transformation.  For example,
+// a zlib stream might take multiple plain-text writes(), and then
+// emit a single compressed chunk some time in the future.
+//
+// Here's how this works:
+//
+// The Transform stream has all the aspects of the readable and writable
+// stream classes.  When you write(chunk), that calls _write(chunk,cb)
+// internally, and returns false if there's a lot of pending writes
+// buffered up.  When you call read(), that calls _read(n) until
+// there's enough pending readable data buffered up.
+//
+// In a transform stream, the written data is placed in a buffer.  When
+// _read(n) is called, it transforms the queued up data, calling the
+// buffered _write cb's as it consumes chunks.  If consuming a single
+// written chunk would result in multiple output chunks, then the first
+// outputted bit calls the readcb, and subsequent chunks just go into
+// the read buffer, and will cause it to emit 'readable' if necessary.
+//
+// This way, back-pressure is actually determined by the reading side,
+// since _read has to be called to start processing a new chunk.  However,
+// a pathological inflate type of transform can cause excessive buffering
+// here.  For example, imagine a stream where every byte of input is
+// interpreted as an integer from 0-255, and then results in that many
+// bytes of output.  Writing the 4 bytes {ff,ff,ff,ff} would result in
+// 1kb of data being output.  In this case, you could write a very small
+// amount of input, and end up with a very large amount of output.  In
+// such a pathological inflating mechanism, there'd be no way to tell
+// the system to stop doing the transform.  A single 4MB write could
+// cause the system to run out of memory.
+//
+// However, even in such a pathological case, only a single written chunk
+// would be consumed, and then the rest would wait (un-transformed) until
+// the results of the previous transformed chunk were consumed.
+
+'use strict';
+
+module.exports = Transform;
+
+const Duplex = require('internal/streams/duplex');
+const util = require('util');
+util.inherits(Transform, Duplex);
+
+
+function TransformState(stream) {
+  this.afterTransform = function(er, data) {
+    return afterTransform(stream, er, data);
+  };
+
+  this.needTransform = false;
+  this.transforming = false;
+  this.writecb = null;
+  this.writechunk = null;
+  this.writeencoding = null;
+}
+
+function afterTransform(stream, er, data) {
+  var ts = stream._transformState;
+  ts.transforming = false;
+
+  var cb = ts.writecb;
+
+  if (!cb)
+    return stream.emit('error', new Error('no writecb in Transform class'));
+
+  ts.writechunk = null;
+  ts.writecb = null;
+
+  if (data !== null && data !== undefined)
+    stream.push(data);
+
+  cb(er);
+
+  var rs = stream._readableState;
+  rs.reading = false;
+  if (rs.needReadable || rs.length < rs.highWaterMark) {
+    stream._read(rs.highWaterMark);
+  }
+}
+
+
+function Transform(options) {
+  if (!(this instanceof Transform))
+    return new Transform(options);
+
+  Duplex.call(this, options);
+
+  this._transformState = new TransformState(this);
+
+  var stream = this;
+
+  // start out asking for a readable event once data is transformed.
+  this._readableState.needReadable = true;
+
+  // we have implemented the _read method, and done the other things
+  // that Readable wants before the first _read call, so unset the
+  // sync guard flag.
+  this._readableState.sync = false;
+
+  if (options) {
+    if (typeof options.transform === 'function')
+      this._transform = options.transform;
+
+    if (typeof options.flush === 'function')
+      this._flush = options.flush;
+  }
+
+  // When the writable side finishes, then flush out anything remaining.
+  this.once('prefinish', function() {
+    if (typeof this._flush === 'function')
+      this._flush(function(er, data) {
+        done(stream, er, data);
+      });
+    else
+      done(stream);
+  });
+}
+
+Transform.prototype.push = function(chunk, encoding) {
+  this._transformState.needTransform = false;
+  return Duplex.prototype.push.call(this, chunk, encoding);
+};
+
+// This is the part where you do stuff!
+// override this function in implementation classes.
+// 'chunk' is an input chunk.
+//
+// Call `push(newChunk)` to pass along transformed output
+// to the readable side.  You may call 'push' zero or more times.
+//
+// Call `cb(err)` when you are done with this chunk.  If you pass
+// an error, then that'll put the hurt on the whole operation.  If you
+// never call cb(), then you'll never get another chunk.
+Transform.prototype._transform = function(chunk, encoding, cb) {
+  throw new Error('_transform() is not implemented');
+};
+
+Transform.prototype._write = function(chunk, encoding, cb) {
+  var ts = this._transformState;
+  ts.writecb = cb;
+  ts.writechunk = chunk;
+  ts.writeencoding = encoding;
+  if (!ts.transforming) {
+    var rs = this._readableState;
+    if (ts.needTransform ||
+        rs.needReadable ||
+        rs.length < rs.highWaterMark)
+      this._read(rs.highWaterMark);
+  }
+};
+
+// Doesn't matter what the args are here.
+// _transform does all the work.
+// That we got here means that the readable side wants more data.
+Transform.prototype._read = function(n) {
+  var ts = this._transformState;
+
+  if (ts.writechunk !== null && ts.writecb && !ts.transforming) {
+    ts.transforming = true;
+    this._transform(ts.writechunk, ts.writeencoding, ts.afterTransform);
+  } else {
+    // mark that we need a transform, so that any data that comes in
+    // will get processed, now that we've asked for it.
+    ts.needTransform = true;
+  }
+};
+
+
+function done(stream, er, data) {
+  if (er)
+    return stream.emit('error', er);
+
+  if (data !== null && data !== undefined)
+    stream.push(data);
+
+  // if there's nothing in the write buffer, then that means
+  // that nothing more will ever be provided
+  var ws = stream._writableState;
+  var ts = stream._transformState;
+
+  if (ws.length)
+    throw new Error('Calling transform done when ws.length != 0');
+
+  if (ts.transforming)
+    throw new Error('Calling transform done when still transforming');
+
+  return stream.push(null);
+}
diff --git a/lib/internal/streams/writable.js b/lib/internal/streams/writable.js
new file mode 100644
index 00000000000000..a0a37fbb7a0421
--- /dev/null
+++ b/lib/internal/streams/writable.js
@@ -0,0 +1,565 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+// A bit simpler than readable streams.
+// Implement an async ._write(chunk, encoding, cb), and it'll handle all
+// the drain event emission and buffering.
+
+'use strict';
+
+module.exports = Writable;
+Writable.WritableState = WritableState;
+
+const util = require('util');
+const internalUtil = require('internal/util');
+const Stream = require('stream');
+const Buffer = require('buffer').Buffer;
+
+util.inherits(Writable, Stream);
+
+function nop() {}
+
+function WritableState(options, stream) {
+  options = options || {};
+
+  // object stream flag to indicate whether or not this stream
+  // contains buffers or objects.
+  this.objectMode = !!options.objectMode;
+
+  if (stream instanceof Stream.Duplex)
+    this.objectMode = this.objectMode || !!options.writableObjectMode;
+
+  // the point at which write() starts returning false
+  // Note: 0 is a valid value, means that we always return false if
+  // the entire buffer is not flushed immediately on write()
+  var hwm = options.highWaterMark;
+  var defaultHwm = this.objectMode ? 16 : 16 * 1024;
+  this.highWaterMark = (hwm || hwm === 0) ? hwm : defaultHwm;
+
+  // cast to ints.
+  this.highWaterMark = ~~this.highWaterMark;
+
+  // drain event flag.
+  this.needDrain = false;
+  // at the start of calling end()
+  this.ending = false;
+  // when end() has been called, and returned
+  this.ended = false;
+  // when 'finish' is emitted
+  this.finished = false;
+
+  // should we decode strings into buffers before passing to _write?
+  // this is here so that some node-core streams can optimize string
+  // handling at a lower level.
+  var noDecode = options.decodeStrings === false;
+  this.decodeStrings = !noDecode;
+
+  // Crypto is kind of old and crusty.  Historically, its default string
+  // encoding is 'binary' so we have to make this configurable.
+  // Everything else in the universe uses 'utf8', though.
+  this.defaultEncoding = options.defaultEncoding || 'utf8';
+
+  // not an actual buffer we keep track of, but a measurement
+  // of how much we're waiting to get pushed to some underlying
+  // socket or file.
+  this.length = 0;
+
+  // a flag to see when we're in the middle of a write.
+  this.writing = false;
+
+  // when true all writes will be buffered until .uncork() call
+  this.corked = 0;
+
+  // a flag to be able to tell if the onwrite cb is called immediately,
+  // or on a later tick.  We set this to true at first, because any
+  // actions that shouldn't happen until "later" should generally also
+  // not happen before the first write call.
+  this.sync = true;
+
+  // a flag to know if we're processing previously buffered items, which
+  // may call the _write() callback in the same tick, so that we don't
+  // end up in an overlapped onwrite situation.
+  this.bufferProcessing = false;
+
+  // the callback that's passed to _write(chunk,cb)
+  this.onwrite = onwrite.bind(undefined, stream);
+
+  // the callback that the user supplies to write(chunk,encoding,cb)
+  this.writecb = null;
+
+  // the amount that is being written when _write is called.
+  this.writelen = 0;
+
+  this.bufferedRequest = null;
+  this.lastBufferedRequest = null;
+
+  // number of pending user-supplied write callbacks
+  // this must be 0 before 'finish' can be emitted
+  this.pendingcb = 0;
+
+  // emit prefinish if the only thing we're waiting for is _write cbs
+  // This is relevant for synchronous Transform streams
+  this.prefinished = false;
+
+  // True if the error was already emitted and should not be thrown again
+  this.errorEmitted = false;
+
+  // count buffered requests
+  this.bufferedRequestCount = 0;
+
+  // allocate the first CorkedRequest, there is always
+  // one allocated and free to use, and we maintain at most two
+  var corkReq = { next: null, entry: null, finish: undefined };
+  corkReq.finish = onCorkedFinish.bind(undefined, corkReq, this);
+  this.corkedRequestsFree = corkReq;
+}
+
+WritableState.prototype.getBuffer = function getBuffer() {
+  var current = this.bufferedRequest;
+  var out = [];
+  while (current) {
+    out.push(current);
+    current = current.next;
+  }
+  return out;
+};
+
+Object.defineProperty(WritableState.prototype, 'buffer', {
+  get: internalUtil.deprecate(function() {
+    return this.getBuffer();
+  }, '_writableState.buffer is deprecated. Use _writableState.getBuffer ' +
+     'instead.', 'DEP0003')
+});
+
+// Test _writableState for inheritance to account for Duplex streams,
+// whose prototype chain only points to Readable.
+var realHasInstance;
+if (typeof Symbol === 'function' && Symbol.hasInstance) {
+  realHasInstance = Function.prototype[Symbol.hasInstance];
+  Object.defineProperty(Writable, Symbol.hasInstance, {
+    value: function(object) {
+      if (realHasInstance.call(this, object))
+        return true;
+
+      return object && object._writableState instanceof WritableState;
+    }
+  });
+} else {
+  realHasInstance = function(object) {
+    return object instanceof this;
+  };
+}
+
+function Writable(options) {
+  // Writable ctor is applied to Duplexes, too.
+  // `realHasInstance` is necessary because using plain `instanceof`
+  // would return false, as no `_writableState` property is attached.
+
+  // Trying to use the custom `instanceof` for Writable here will also break the
+  // Node.js LazyTransform implementation, which has a non-trivial getter for
+  // `_writableState` that would lead to infinite recursion.
+  if (!(realHasInstance.call(Writable, this)) &&
+      !(this instanceof Stream.Duplex)) {
+    return new Writable(options);
+  }
+
+  this._writableState = new WritableState(options, this);
+
+  // legacy.
+  this.writable = true;
+
+  if (options) {
+    if (typeof options.write === 'function')
+      this._write = options.write;
+
+    if (typeof options.writev === 'function')
+      this._writev = options.writev;
+  }
+
+  Stream.call(this);
+}
+
+// Otherwise people can pipe Writable streams, which is just wrong.
+Writable.prototype.pipe = function() {
+  this.emit('error', new Error('Cannot pipe, not readable'));
+};
+
+
+function writeAfterEnd(stream, cb) {
+  var er = new Error('write after end');
+  // TODO: defer error events consistently everywhere, not just the cb
+  stream.emit('error', er);
+  process.nextTick(cb, er);
+}
+
+// Checks that a user-supplied chunk is valid, especially for the particular
+// mode the stream is in. Currently this means that `null` is never accepted
+// and undefined/non-string values are only allowed in object mode.
+function validChunk(stream, state, chunk, cb) {
+  var valid = true;
+  var er = false;
+
+  if (chunk === null) {
+    er = new TypeError('May not write null values to stream');
+  } else if (typeof chunk !== 'string' &&
+             chunk !== undefined &&
+             !state.objectMode) {
+    er = new TypeError('Invalid non-string/buffer chunk');
+  }
+  if (er) {
+    stream.emit('error', er);
+    process.nextTick(cb, er);
+    valid = false;
+  }
+  return valid;
+}
+
+Writable.prototype.write = function(chunk, encoding, cb) {
+  var state = this._writableState;
+  var ret = false;
+  var isBuf = (chunk instanceof Buffer);
+
+  if (typeof encoding === 'function') {
+    cb = encoding;
+    encoding = null;
+  }
+
+  if (isBuf)
+    encoding = 'buffer';
+  else if (!encoding)
+    encoding = state.defaultEncoding;
+
+  if (typeof cb !== 'function')
+    cb = nop;
+
+  if (state.ended)
+    writeAfterEnd(this, cb);
+  else if (isBuf || validChunk(this, state, chunk, cb)) {
+    state.pendingcb++;
+    ret = writeOrBuffer(this, state, isBuf, chunk, encoding, cb);
+  }
+
+  return ret;
+};
+
+Writable.prototype.cork = function() {
+  var state = this._writableState;
+
+  state.corked++;
+};
+
+Writable.prototype.uncork = function() {
+  var state = this._writableState;
+
+  if (state.corked) {
+    state.corked--;
+
+    if (!state.writing &&
+        !state.corked &&
+        !state.finished &&
+        !state.bufferProcessing &&
+        state.bufferedRequest)
+      clearBuffer(this, state);
+  }
+};
+
+Writable.prototype.setDefaultEncoding = function setDefaultEncoding(encoding) {
+  // node::ParseEncoding() requires lower case.
+  if (typeof encoding === 'string')
+    encoding = encoding.toLowerCase();
+  if (!Buffer.isEncoding(encoding))
+    throw new TypeError('Unknown encoding: ' + encoding);
+  this._writableState.defaultEncoding = encoding;
+  return this;
+};
+
+function decodeChunk(state, chunk, encoding) {
+  if (!state.objectMode &&
+      state.decodeStrings !== false &&
+      typeof chunk === 'string') {
+    chunk = Buffer.from(chunk, encoding);
+  }
+  return chunk;
+}
+
+// if we're already writing something, then just put this
+// in the queue, and wait our turn.  Otherwise, call _write
+// If we return false, then we need a drain event, so set that flag.
+function writeOrBuffer(stream, state, isBuf, chunk, encoding, cb) {
+  if (!isBuf) {
+    var newChunk = decodeChunk(state, chunk, encoding);
+    if (chunk !== newChunk) {
+      encoding = 'buffer';
+      chunk = newChunk;
+    }
+  }
+  var len = state.objectMode ? 1 : chunk.length;
+
+  state.length += len;
+
+  var ret = state.length < state.highWaterMark;
+  // we must ensure that previous needDrain will not be reset to false.
+  if (!ret)
+    state.needDrain = true;
+
+  if (state.writing || state.corked) {
+    var last = state.lastBufferedRequest;
+    state.lastBufferedRequest = { chunk, encoding, callback: cb, next: null };
+    if (last) {
+      last.next = state.lastBufferedRequest;
+    } else {
+      state.bufferedRequest = state.lastBufferedRequest;
+    }
+    state.bufferedRequestCount += 1;
+  } else {
+    doWrite(stream, state, false, len, chunk, encoding, cb);
+  }
+
+  return ret;
+}
+
+function doWrite(stream, state, writev, len, chunk, encoding, cb) {
+  state.writelen = len;
+  state.writecb = cb;
+  state.writing = true;
+  state.sync = true;
+  if (writev)
+    stream._writev(chunk, state.onwrite);
+  else
+    stream._write(chunk, encoding, state.onwrite);
+  state.sync = false;
+}
+
+function onwriteError(stream, state, sync, er, cb) {
+  --state.pendingcb;
+  if (sync)
+    process.nextTick(cb, er);
+  else
+    cb(er);
+
+  stream._writableState.errorEmitted = true;
+  stream.emit('error', er);
+}
+
+function onwriteStateUpdate(state) {
+  state.writing = false;
+  state.writecb = null;
+  state.length -= state.writelen;
+  state.writelen = 0;
+}
+
+function onwrite(stream, er) {
+  var state = stream._writableState;
+  var sync = state.sync;
+  var cb = state.writecb;
+
+  onwriteStateUpdate(state);
+
+  if (er)
+    onwriteError(stream, state, sync, er, cb);
+  else {
+    // Check if we're actually ready to finish, but don't emit yet
+    var finished = needFinish(state);
+
+    if (!finished &&
+        !state.corked &&
+        !state.bufferProcessing &&
+        state.bufferedRequest) {
+      clearBuffer(stream, state);
+    }
+
+    if (sync) {
+      process.nextTick(afterWrite, stream, state, finished, cb);
+    } else {
+      afterWrite(stream, state, finished, cb);
+    }
+  }
+}
+
+function afterWrite(stream, state, finished, cb) {
+  if (!finished)
+    onwriteDrain(stream, state);
+  state.pendingcb--;
+  cb();
+  finishMaybe(stream, state);
+}
+
+// Must force callback to be called on nextTick, so that we don't
+// emit 'drain' before the write() consumer gets the 'false' return
+// value, and has a chance to attach a 'drain' listener.
+function onwriteDrain(stream, state) {
+  if (state.length === 0 && state.needDrain) {
+    state.needDrain = false;
+    stream.emit('drain');
+  }
+}
+
+// if there's something in the buffer waiting, then process it
+function clearBuffer(stream, state) {
+  state.bufferProcessing = true;
+  var entry = state.bufferedRequest;
+
+  if (stream._writev && entry && entry.next) {
+    // Fast case, write everything using _writev()
+    var l = state.bufferedRequestCount;
+    var buffer = new Array(l);
+    var holder = state.corkedRequestsFree;
+    holder.entry = entry;
+
+    var count = 0;
+    while (entry) {
+      buffer[count] = entry;
+      entry = entry.next;
+      count += 1;
+    }
+
+    doWrite(stream, state, true, state.length, buffer, '', holder.finish);
+
+    // doWrite is almost always async, defer these to save a bit of time
+    // as the hot path ends with doWrite
+    state.pendingcb++;
+    state.lastBufferedRequest = null;
+    if (holder.next) {
+      state.corkedRequestsFree = holder.next;
+      holder.next = null;
+    } else {
+      var corkReq = { next: null, entry: null, finish: undefined };
+      corkReq.finish = onCorkedFinish.bind(undefined, corkReq, state);
+      state.corkedRequestsFree = corkReq;
+    }
+  } else {
+    // Slow case, write chunks one-by-one
+    while (entry) {
+      var chunk = entry.chunk;
+      var encoding = entry.encoding;
+      var cb = entry.callback;
+      var len = state.objectMode ? 1 : chunk.length;
+
+      doWrite(stream, state, false, len, chunk, encoding, cb);
+      entry = entry.next;
+      // if we didn't call the onwrite immediately, then
+      // it means that we need to wait until it does.
+      // also, that means that the chunk and cb are currently
+      // being processed, so move the buffer counter past them.
+      if (state.writing) {
+        break;
+      }
+    }
+
+    if (entry === null)
+      state.lastBufferedRequest = null;
+  }
+
+  state.bufferedRequestCount = 0;
+  state.bufferedRequest = entry;
+  state.bufferProcessing = false;
+}
+
+Writable.prototype._write = function(chunk, encoding, cb) {
+  cb(new Error('_write() is not implemented'));
+};
+
+Writable.prototype._writev = null;
+
+Writable.prototype.end = function(chunk, encoding, cb) {
+  var state = this._writableState;
+
+  if (typeof chunk === 'function') {
+    cb = chunk;
+    chunk = null;
+    encoding = null;
+  } else if (typeof encoding === 'function') {
+    cb = encoding;
+    encoding = null;
+  }
+
+  if (chunk !== null && chunk !== undefined)
+    this.write(chunk, encoding);
+
+  // .end() fully uncorks
+  if (state.corked) {
+    state.corked = 1;
+    this.uncork();
+  }
+
+  // ignore unnecessary end() calls.
+  if (!state.ending && !state.finished)
+    endWritable(this, state, cb);
+};
+
+
+function needFinish(state) {
+  return (state.ending &&
+          state.length === 0 &&
+          state.bufferedRequest === null &&
+          !state.finished &&
+          !state.writing);
+}
+
+function prefinish(stream, state) {
+  if (!state.prefinished) {
+    state.prefinished = true;
+    stream.emit('prefinish');
+  }
+}
+
+function finishMaybe(stream, state) {
+  var need = needFinish(state);
+  if (need) {
+    if (state.pendingcb === 0) {
+      prefinish(stream, state);
+      state.finished = true;
+      stream.emit('finish');
+    } else {
+      prefinish(stream, state);
+    }
+  }
+  return need;
+}
+
+function endWritable(stream, state, cb) {
+  state.ending = true;
+  finishMaybe(stream, state);
+  if (cb) {
+    if (state.finished)
+      process.nextTick(cb);
+    else
+      stream.once('finish', cb);
+  }
+  state.ended = true;
+  stream.writable = false;
+}
+
+function onCorkedFinish(corkReq, state, err) {
+  var entry = corkReq.entry;
+  corkReq.entry = null;
+  while (entry) {
+    var cb = entry.callback;
+    state.pendingcb--;
+    cb(err);
+    entry = entry.next;
+  }
+  if (state.corkedRequestsFree) {
+    state.corkedRequestsFree.next = corkReq;
+  } else {
+    state.corkedRequestsFree = corkReq;
+  }
+}
diff --git a/lib/stream.js b/lib/stream.js
index dca4f50fc09eac..6674a0e15c7c2a 100644
--- a/lib/stream.js
+++ b/lib/stream.js
@@ -25,11 +25,11 @@
 // to avoid a cross-reference(require) issues
 const Stream = module.exports = require('internal/streams/legacy');
 
-Stream.Readable = require('_stream_readable');
-Stream.Writable = require('_stream_writable');
-Stream.Duplex = require('_stream_duplex');
-Stream.Transform = require('_stream_transform');
-Stream.PassThrough = require('_stream_passthrough');
+Stream.Readable = require('internal/streams/readable');
+Stream.Writable = require('internal/streams/writable');
+Stream.Duplex = require('internal/streams/duplex');
+Stream.Transform = require('internal/streams/transform');
+Stream.PassThrough = require('internal/streams/passthrough');
 
 // Backwards-compat with node 0.4.x
 Stream.Stream = Stream;
diff --git a/lib/zlib.js b/lib/zlib.js
index 00be56dffc44fb..b6162366e99ced 100644
--- a/lib/zlib.js
+++ b/lib/zlib.js
@@ -23,7 +23,7 @@
 
 const Buffer = require('buffer').Buffer;
 const internalUtil = require('internal/util');
-const Transform = require('_stream_transform');
+const Transform = require('internal/streams/transform');
 const binding = process.binding('zlib');
 const assert = require('assert').ok;
 const kMaxLength = require('buffer').kMaxLength;
diff --git a/node.gyp b/node.gyp
index c20b07a66c6ea4..28a7011d862f58 100644
--- a/node.gyp
+++ b/node.gyp
@@ -101,6 +101,11 @@
       'lib/internal/util.js',
       'lib/internal/v8_prof_polyfill.js',
       'lib/internal/v8_prof_processor.js',
+      'lib/internal/streams/readable.js',
+      'lib/internal/streams/writable.js',
+      'lib/internal/streams/duplex.js',
+      'lib/internal/streams/transform.js',
+      'lib/internal/streams/passthrough.js',
       'lib/internal/streams/lazy_transform.js',
       'lib/internal/streams/BufferList.js',
       'lib/internal/streams/legacy.js',
diff --git a/test/message/stdin_messages.out b/test/message/stdin_messages.out
index ad1688f15d09b8..f2c811c883e823 100644
--- a/test/message/stdin_messages.out
+++ b/test/message/stdin_messages.out
@@ -11,7 +11,7 @@ SyntaxError: Strict mode code may not include a with statement
     at Socket.<anonymous> (bootstrap_node.js:*:*)
     at emitNone (events.js:*:*)
     at Socket.emit (events.js:*:*)
-    at endReadableNT (_stream_readable.js:*:*)
+    at endReadableNT (internal/streams/readable.js:*:*)
     at _combinedTickCallback (internal/process/next_tick.js:*:*)
 42
 42
@@ -29,7 +29,7 @@ Error: hello
     at Socket.<anonymous> (bootstrap_node.js:*:*)
     at emitNone (events.js:*:*)
     at Socket.emit (events.js:*:*)
-    at endReadableNT (_stream_readable.js:*:*)
+    at endReadableNT (internal/streams/readable.js:*:*)
 [stdin]:1
 throw new Error("hello")
 ^
@@ -44,7 +44,7 @@ Error: hello
     at Socket.<anonymous> (bootstrap_node.js:*:*)
     at emitNone (events.js:*:*)
     at Socket.emit (events.js:*:*)
-    at endReadableNT (_stream_readable.js:*:*)
+    at endReadableNT (internal/streams/readable.js:*:*)
 100
 [stdin]:1
 var x = 100; y = x;
@@ -60,7 +60,7 @@ ReferenceError: y is not defined
     at Socket.<anonymous> (bootstrap_node.js:*:*)
     at emitNone (events.js:*:*)
     at Socket.emit (events.js:*:*)
-    at endReadableNT (_stream_readable.js:*:*)
+    at endReadableNT (internal/streams/readable.js:*:*)
 
 [stdin]:1
 var ______________________________________________; throw 10
diff --git a/test/parallel/test-stream-internals-usage-deprecation.js b/test/parallel/test-stream-internals-usage-deprecation.js
new file mode 100644
index 00000000000000..bac0b38750c781
--- /dev/null
+++ b/test/parallel/test-stream-internals-usage-deprecation.js
@@ -0,0 +1,35 @@
+// Flags: --no-warnings
+// The flag suppresses stderr output but the warning event will still emit
+'use strict';
+
+const common = require('../common');
+const assert = require('assert');
+
+const mods = [
+  '_stream_readable',
+  '_stream_writable',
+  '_stream_duplex',
+  '_stream_transform',
+  '_stream_passthrough'
+];
+
+// we cannot use a forEach, the warning is emitted asynchronously
+function test() {
+  const mod = mods.shift();
+
+  if (!mod) {
+    return;
+  }
+
+  process.once('warning', common.mustCall((warning) => {
+    assert.ok(warning instanceof Error);
+    assert.strictEqual(warning.message,
+                       `The ${mod}.js module is deprecated. Please use stream`);
+    assert.strictEqual(warning.code, 'DEP00XX');
+    test();
+  }));
+
+  require(mod);
+}
+
+test();
diff --git a/test/parallel/test-stream-pipe-after-end.js b/test/parallel/test-stream-pipe-after-end.js
index 02792b44554348..bd4179c0da59fb 100644
--- a/test/parallel/test-stream-pipe-after-end.js
+++ b/test/parallel/test-stream-pipe-after-end.js
@@ -22,8 +22,8 @@
 'use strict';
 const common = require('../common');
 const assert = require('assert');
-const Readable = require('_stream_readable');
-const Writable = require('_stream_writable');
+const Readable = require('stream').Readable;
+const Writable = require('stream').Writable;
 const util = require('util');
 
 util.inherits(TestReadable, Readable);
diff --git a/test/parallel/test-stream2-base64-single-char-read-end.js b/test/parallel/test-stream2-base64-single-char-read-end.js
index 2e400c2f97ec9c..e210bad44f0f91 100644
--- a/test/parallel/test-stream2-base64-single-char-read-end.js
+++ b/test/parallel/test-stream2-base64-single-char-read-end.js
@@ -20,9 +20,10 @@
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 'use strict';
+
 require('../common');
-const R = require('_stream_readable');
-const W = require('_stream_writable');
+const R = require('stream').Readable;
+const W = require('stream').Writable;
 const assert = require('assert');
 
 const src = new R({encoding: 'base64'});
diff --git a/test/parallel/test-stream2-compatibility.js b/test/parallel/test-stream2-compatibility.js
index 45834ee99e5961..c14774d1eccade 100644
--- a/test/parallel/test-stream2-compatibility.js
+++ b/test/parallel/test-stream2-compatibility.js
@@ -21,8 +21,8 @@
 
 'use strict';
 require('../common');
-const R = require('_stream_readable');
-const W = require('_stream_writable');
+const R = require('stream').Readable;
+const W = require('stream').Writable;
 const assert = require('assert');
 
 const util = require('util');
diff --git a/test/parallel/test-stream2-decode-partial.js b/test/parallel/test-stream2-decode-partial.js
index b43101dbc84c3a..08b1eb3833207b 100644
--- a/test/parallel/test-stream2-decode-partial.js
+++ b/test/parallel/test-stream2-decode-partial.js
@@ -1,6 +1,6 @@
 'use strict';
 require('../common');
-const Readable = require('_stream_readable');
+const Readable = require('stream').Readable;
 const assert = require('assert');
 
 let buf = '';
diff --git a/test/parallel/test-stream2-objects.js b/test/parallel/test-stream2-objects.js
index 159286a4322257..9989c8fada119c 100644
--- a/test/parallel/test-stream2-objects.js
+++ b/test/parallel/test-stream2-objects.js
@@ -22,8 +22,8 @@
 'use strict';
 
 const common = require('../common');
-const Readable = require('_stream_readable');
-const Writable = require('_stream_writable');
+const Readable = require('stream').Readable;
+const Writable = require('stream').Writable;
 const assert = require('assert');
 
 // tiny node-tap lookalike.
diff --git a/test/parallel/test-stream2-readable-from-list.js b/test/parallel/test-stream2-readable-from-list.js
index 6f677ce8a4155c..0598f6d85a4660 100644
--- a/test/parallel/test-stream2-readable-from-list.js
+++ b/test/parallel/test-stream2-readable-from-list.js
@@ -23,7 +23,7 @@
 'use strict';
 require('../common');
 const assert = require('assert');
-const fromList = require('_stream_readable')._fromList;
+const fromList = require('stream').Readable._fromList;
 const BufferList = require('internal/streams/BufferList');
 
 // tiny node-tap lookalike.
diff --git a/test/parallel/test-stream2-readable-non-empty-end.js b/test/parallel/test-stream2-readable-non-empty-end.js
index 4299f31ea12986..781b28ff63d437 100644
--- a/test/parallel/test-stream2-readable-non-empty-end.js
+++ b/test/parallel/test-stream2-readable-non-empty-end.js
@@ -22,7 +22,7 @@
 'use strict';
 const common = require('../common');
 const assert = require('assert');
-const Readable = require('_stream_readable');
+const Readable = require('stream').Readable;
 
 let len = 0;
 const chunks = new Array(10);
diff --git a/test/parallel/test-stream2-readable-wrap-empty.js b/test/parallel/test-stream2-readable-wrap-empty.js
index 39bc509a394022..66711fc1e44026 100644
--- a/test/parallel/test-stream2-readable-wrap-empty.js
+++ b/test/parallel/test-stream2-readable-wrap-empty.js
@@ -22,7 +22,7 @@
 'use strict';
 const common = require('../common');
 
-const Readable = require('_stream_readable');
+const Readable = require('stream').Readable;
 const EE = require('events').EventEmitter;
 
 const oldStream = new EE();
diff --git a/test/parallel/test-stream2-readable-wrap.js b/test/parallel/test-stream2-readable-wrap.js
index fe9e8ce30dcf93..f429b36efa66ca 100644
--- a/test/parallel/test-stream2-readable-wrap.js
+++ b/test/parallel/test-stream2-readable-wrap.js
@@ -22,8 +22,8 @@
 'use strict';
 const common = require('../common');
 const assert = require('assert');
-const Readable = require('_stream_readable');
-const Writable = require('_stream_writable');
+const Readable = require('stream').Readable;
+const Writable = require('stream').Writable;
 const EE = require('events').EventEmitter;
 
 function runTest(highWaterMark, objectMode, produce) {
diff --git a/test/parallel/test-stream2-set-encoding.js b/test/parallel/test-stream2-set-encoding.js
index 08d9298c6d2138..a53ac6b8688b1e 100644
--- a/test/parallel/test-stream2-set-encoding.js
+++ b/test/parallel/test-stream2-set-encoding.js
@@ -22,7 +22,7 @@
 'use strict';
 require('../common');
 const assert = require('assert');
-const R = require('_stream_readable');
+const R = require('stream').Readable;
 const util = require('util');
 
 // tiny node-tap lookalike.
diff --git a/test/parallel/test-stream2-transform.js b/test/parallel/test-stream2-transform.js
index 6e59d2d1787bf2..ec97083ac8a127 100644
--- a/test/parallel/test-stream2-transform.js
+++ b/test/parallel/test-stream2-transform.js
@@ -22,8 +22,8 @@
 'use strict';
 require('../common');
 const assert = require('assert');
-const PassThrough = require('_stream_passthrough');
-const Transform = require('_stream_transform');
+const PassThrough = require('stream').PassThrough;
+const Transform = require('stream').Transform;
 
 // tiny node-tap lookalike.
 const tests = [];
diff --git a/test/parallel/test-stream2-writable.js b/test/parallel/test-stream2-writable.js
index c983a26c400b91..f872fb397be14b 100644
--- a/test/parallel/test-stream2-writable.js
+++ b/test/parallel/test-stream2-writable.js
@@ -22,8 +22,8 @@
 'use strict';
 
 const common = require('../common');
-const W = require('_stream_writable');
-const D = require('_stream_duplex');
+const W = require('stream').Writable;
+const D = require('stream').Duplex;
 const assert = require('assert');
 
 const util = require('util');