diff --git a/src/Io/ChunkedEncoder.php b/src/Io/ChunkedEncoder.php
new file mode 100644
index 0000000..3b74e0c
--- /dev/null
+++ b/src/Io/ChunkedEncoder.php
@@ -0,0 +1,93 @@
+<?php
+
+namespace Clue\React\Buzz\Io;
+
+use Evenement\EventEmitter;
+use React\Stream\ReadableStreamInterface;
+use React\Stream\Util;
+use React\Stream\WritableStreamInterface;
+
+/**
+ * [Internal] Encodes given payload stream with "Transfer-Encoding: chunked" and emits encoded data
+ *
+ * This is used internally to encode outgoing requests with this encoding.
+ *
+ * @internal
+ * @link https://github.com/reactphp/http/blob/master/src/Io/ChunkedEncoder.php Originally from react/http
+ */
+class ChunkedEncoder extends EventEmitter implements ReadableStreamInterface
+{
+    private $input;
+    private $closed = false;
+
+    public function __construct(ReadableStreamInterface $input)
+    {
+        $this->input = $input;
+
+        $this->input->on('data', array($this, 'handleData'));
+        $this->input->on('end', array($this, 'handleEnd'));
+        $this->input->on('error', array($this, 'handleError'));
+        $this->input->on('close', array($this, 'close'));
+    }
+
+    public function isReadable()
+    {
+        return !$this->closed && $this->input->isReadable();
+    }
+
+    public function pause()
+    {
+        $this->input->pause();
+    }
+
+    public function resume()
+    {
+        $this->input->resume();
+    }
+
+    public function pipe(WritableStreamInterface $dest, array $options = array())
+    {
+        return Util::pipe($this, $dest, $options);
+    }
+
+    public function close()
+    {
+        if ($this->closed) {
+            return;
+        }
+
+        $this->closed = true;
+        $this->input->close();
+
+        $this->emit('close');
+        $this->removeAllListeners();
+    }
+
+    /** @internal */
+    public function handleData($data)
+    {
+        if ($data !== '') {
+            $this->emit('data', array(
+                dechex(strlen($data)) . "\r\n" . $data . "\r\n"
+            ));
+        }
+    }
+
+    /** @internal */
+    public function handleError(\Exception $e)
+    {
+        $this->emit('error', array($e));
+        $this->close();
+    }
+
+    /** @internal */
+    public function handleEnd()
+    {
+        $this->emit('data', array("0\r\n\r\n"));
+
+        if (!$this->closed) {
+            $this->emit('end');
+            $this->close();
+        }
+    }
+}
diff --git a/src/Io/Sender.php b/src/Io/Sender.php
index f105d86..6b99b6f 100644
--- a/src/Io/Sender.php
+++ b/src/Io/Sender.php
@@ -124,19 +124,12 @@ public function send(RequestInterface $request)
 
         if ($body instanceof ReadableStreamInterface) {
             if ($body->isReadable()) {
-                if ($size !== null) {
-                    // length is known => just write to request
-                    $body->pipe($requestStream);
-                } else {
-                    // length unknown => apply chunked transfer-encoding
-                    // this should be moved somewhere else obviously
-                    $body->on('data', function ($data) use ($requestStream) {
-                        $requestStream->write(dechex(strlen($data)) . "\r\n" . $data . "\r\n");
-                    });
-                    $body->on('end', function() use ($requestStream) {
-                        $requestStream->end("0\r\n\r\n");
-                    });
+                // length unknown => apply chunked transfer-encoding
+                if ($size === null) {
+                    $body = new ChunkedEncoder($body);
                 }
+
+                $body->pipe($requestStream);
             } else {
                 // stream is not readable => end request without body
                 $requestStream->end();
diff --git a/tests/FunctionalBrowserTest.php b/tests/FunctionalBrowserTest.php
index fe4a5f2..fe24577 100644
--- a/tests/FunctionalBrowserTest.php
+++ b/tests/FunctionalBrowserTest.php
@@ -301,9 +301,7 @@ public function testPostStreamChunked()
         $stream = new ThroughStream();
 
         $this->loop->addTimer(0.001, function () use ($stream) {
-            $stream->emit('data', array('hello world'));
-            $stream->emit('end');
-            $stream->close();
+            $stream->end('hello world');
         });
 
         $response = Block\await($this->browser->post($this->base . 'post', array(), $stream), $this->loop);
diff --git a/tests/Io/ChunkedEncoderTest.php b/tests/Io/ChunkedEncoderTest.php
new file mode 100644
index 0000000..c449033
--- /dev/null
+++ b/tests/Io/ChunkedEncoderTest.php
@@ -0,0 +1,120 @@
+<?php
+
+namespace Clue\Tests\React\Buzz\Io;
+
+use Clue\React\Buzz\Io\ChunkedEncoder;
+use PHPUnit\Framework\TestCase;
+use React\Stream\ThroughStream;
+
+class ChunkedEncoderTest extends TestCase
+{
+    private $input;
+    private $chunkedStream;
+
+    public function setUp()
+    {
+        $this->input = new ThroughStream();
+        $this->chunkedStream = new ChunkedEncoder($this->input);
+    }
+
+    public function testChunked()
+    {
+        $this->chunkedStream->on('data', $this->expectCallableOnceWith("5\r\nhello\r\n"));
+        $this->input->emit('data', array('hello'));
+    }
+
+    public function testEmptyString()
+    {
+        $this->chunkedStream->on('data', $this->expectCallableNever());
+        $this->input->emit('data', array(''));
+    }
+
+    public function testBiggerStringToCheckHexValue()
+    {
+        $this->chunkedStream->on('data', $this->expectCallableOnceWith("1a\r\nabcdefghijklmnopqrstuvwxyz\r\n"));
+        $this->input->emit('data', array('abcdefghijklmnopqrstuvwxyz'));
+    }
+
+    public function testHandleClose()
+    {
+        $this->chunkedStream->on('close', $this->expectCallableOnce());
+
+        $this->input->close();
+
+        $this->assertFalse($this->chunkedStream->isReadable());
+    }
+
+    public function testHandleError()
+    {
+        $this->chunkedStream->on('error', $this->expectCallableOnce());
+        $this->chunkedStream->on('close', $this->expectCallableOnce());
+
+        $this->input->emit('error', array(new \RuntimeException()));
+
+        $this->assertFalse($this->chunkedStream->isReadable());
+    }
+
+    public function testPauseStream()
+    {
+        $input = $this->getMockBuilder('React\Stream\ReadableStreamInterface')->getMock();
+        $input->expects($this->once())->method('pause');
+
+        $parser = new ChunkedEncoder($input);
+        $parser->pause();
+    }
+
+    public function testResumeStream()
+    {
+        $input = $this->getMockBuilder('React\Stream\ReadableStreamInterface')->getMock();
+        $input->expects($this->once())->method('pause');
+
+        $parser = new ChunkedEncoder($input);
+        $parser->pause();
+        $parser->resume();
+    }
+
+    public function testPipeStream()
+    {
+        $dest = $this->getMockBuilder('React\Stream\WritableStreamInterface')->getMock();
+
+        $ret = $this->chunkedStream->pipe($dest);
+
+        $this->assertSame($dest, $ret);
+    }
+
+    protected function expectCallableOnce()
+    {
+        $mock = $this->createCallableMock();
+        $mock
+            ->expects($this->once())
+            ->method('__invoke');
+
+        return $mock;
+    }
+
+    protected function expectCallableOnceWith($value)
+    {
+        $mock = $this->createCallableMock();
+        $mock
+            ->expects($this->once())
+            ->method('__invoke')
+            ->with($value);
+
+        return $mock;
+    }
+
+    protected function expectCallableNever()
+    {
+        $mock = $this->createCallableMock();
+        $mock
+            ->expects($this->never())
+            ->method('__invoke');
+
+        return $mock;
+    }
+
+    protected function createCallableMock()
+    {
+        return $this->getMockBuilder('stdClass')->setMethods(array('__invoke'))->getMock();
+    }
+}
diff --git a/tests/Io/SenderTest.php b/tests/Io/SenderTest.php
index be4eaa9..1deb0f2 100644
--- a/tests/Io/SenderTest.php
+++ b/tests/Io/SenderTest.php
@@ -111,6 +111,44 @@ public function testSendPostStreamWillAutomaticallySendTransferEncodingChunked()
         $sender->send($request);
     }
 
+    public function testSendPostStreamWillAutomaticallyPipeChunkEncodeBodyForWriteAndRespectRequestThrottling()
+    {
+        $outgoing = $this->getMockBuilder('React\HttpClient\Request')->disableOriginalConstructor()->getMock();
+        $outgoing->expects($this->once())->method('isWritable')->willReturn(true);
+        $outgoing->expects($this->once())->method('write')->with("5\r\nhello\r\n")->willReturn(false);
+
+        $client = $this->getMockBuilder('React\HttpClient\Client')->disableOriginalConstructor()->getMock();
+        $client->expects($this->once())->method('request')->willReturn($outgoing);
+
+        $sender = new Sender($client, $this->getMockBuilder('Clue\React\Buzz\Message\MessageFactory')->getMock());
+
+        $stream = new ThroughStream();
+        $request = new Request('POST', 'http://www.google.com/', array(), new ReadableBodyStream($stream));
+        $sender->send($request);
+
+        $ret = $stream->write('hello');
+        $this->assertFalse($ret);
+    }
+
+    public function testSendPostStreamWillAutomaticallyPipeChunkEncodeBodyForEnd()
+    {
+        $outgoing = $this->getMockBuilder('React\HttpClient\Request')->disableOriginalConstructor()->getMock();
+        $outgoing->expects($this->once())->method('isWritable')->willReturn(true);
+        $outgoing->expects($this->once())->method('write')->with("0\r\n\r\n")->willReturn(false);
+        $outgoing->expects($this->once())->method('end')->with(null);
+
+        $client = $this->getMockBuilder('React\HttpClient\Client')->disableOriginalConstructor()->getMock();
+        $client->expects($this->once())->method('request')->willReturn($outgoing);
+
+        $sender = new Sender($client, $this->getMockBuilder('Clue\React\Buzz\Message\MessageFactory')->getMock());
+
+        $stream = new ThroughStream();
+        $request = new Request('POST', 'http://www.google.com/', array(), new ReadableBodyStream($stream));
+        $sender->send($request);
+
+        $stream->end();
+    }
+
     public function testSendPostStreamWithExplicitContentLengthWillSendHeaderAsIs()
     {
         $client = $this->getMockBuilder('React\HttpClient\Client')->disableOriginalConstructor()->getMock();