fixup: simplify

Author: ronag

lib/internal/streams/duplexpair.js

@@ -20,10 +20,10 @@ class DuplexSocket extends Duplex {
   }
 
   _write(chunk, encoding, callback) {
-    this[kOtherSide].push(chunk);
-    if (!this[kOtherSide].readableLength) {
+    if (chunk.length === 0) {
       process.nextTick(callback);
     } else {
+      this[kOtherSide].push(chunk);
       this[kOtherSide][kCallback] = callback;
     }
   }

test/common/duplexpair.js

@@ -24,10 +24,10 @@ class DuplexSocket extends Duplex {
   _write(chunk, encoding, callback) {
     assert.notStrictEqual(this[kOtherSide], null);
     assert.strictEqual(this[kOtherSide][kCallback], null);
-    this[kOtherSide].push(chunk);
-    if (!this[kOtherSide].readableLength) {
+    if (chunk.length === 0) {
       process.nextTick(callback);
     } else {
+      this[kOtherSide].push(chunk);
       this[kOtherSide][kCallback] = callback;
     }
   }