title: pipe issue with Node js Duplex Stream example
body: <p>I would like to write an example for node js duplex streams, such that 
  for two duplex streams A and B</p>
  
  <p>If A writes something it should be read by stream B and vice versa</p>
  
  <p>I have written it in this way:</p>
  
  <pre><code>const Duplex = require('stream').Duplex;
  
  class MyDuplex extends Duplex {
      constructor(name, options) {
          super(options);
          this.name = name;
      }
  
      _read(size) {}
  
      _write(chunk, encoding, callback) {
          console.log(this.name + ' writes: ' + chunk + '\n');
          callback();
      }
  }
  
  let aStream = new MyDuplex('A');
  let bStream = new MyDuplex('B');
  
  
  aStream.pipe(bStream).pipe(aStream);
  
  aStream.on('data', (chunk) =&gt; {
      console.log('A read: ' + chunk + '\n');
  })
  
  aStream.write('Hello B!');
  
  bStream.on('data', (chunk) =&gt; {
      console.log('B read: ' + chunk + '\n');
  })
  bStream.write('Hello A!');`
  </code></pre>
  
  <p>Now even though I have piped the two streams, not getting the desired Output: </p>
  
  <pre><code>A writes: Hello B!
  B reads: Hello B!
  B writes: Hello A! 
  A reads: Hello A!
  </code></pre>