anchor.diff:      this._backhandler = null;
       this.push();
     }
  -
  +  
     void end(){
       if(this.closed) return;
       (this.paused ? this.resume() : this.push());
  
positive.code:   void buffer(){
      this._draining = true;
      this.stream.pause();
      this._initBuffer();
    }
  
    void endBuffer(){
      this.drain();
      this._draining = false;
      this._destroyBuffer();
      this.stream.resume();
    }
  
  
negative.code:     this.end();
      this.done.then((n){
        this._streams.free();
        this._handler = this._backhandler = this._drain = null;
      });
    }
    
  