simplified stream construction

 Easy way to create a Stream that is both readable and writable.
 .
    Pass in optional write and end methods.
    through takes care of pause/resume logic if you use this.queue(data)
    instead of this.emit('data', data).
    Use this.pause() and this.resume() to manage flow.
    Check this.paused to see current flow state.
    (write always returns !this.paused).
 .
 This function is the basis for most of the synchronous streams in event-stream.
 .
 Node.js is an event-based server-side JavaScript engine.