anchor.diff:    void buffer(){
       this._draining = true;
       this.stream.pause();
  -    this._initBuffer();
     }
   
     void endBuffer(){
       this.drain();
       this._draining = false;
  -    this._destroyBuffer();
       this.stream.resume();
     }
   
  
positive.code:   final Completer _done = new Completer();
    bool _shouldShutDown = false;
    Function _handler;
    Function _backhandler;
    
    static create() => new Streamable();
  
negative.code:     this.end();
      this.done.then((n){
        this._streams.free();
        this._handler = this._backhandler = this._drain = null;
      });
    }
    
  