anchor.diff:      } while(delta.inSeconds < 1);
   
       final int output = input.x * input.y;
  -    reply.send(output);
  +    return output;
     });
   }
  -
  -
  
positive.code:   final Stage _stage;
    final core.AffineTransform _tx;
    final Dragger _dragger;
    final _DemoMapper _demoMapper;
  
    core.Coordinate _mouseLocation;
    bool _frameRequested = false;
  
negative.code:   }
  
    DraggerDemo._internal(this._canvas, this._stage, this._tx, this._dragger) :
      _demoMapper = new _DemoValue() {
      _canvas.on.mouseMove.add(_canvas_mouseMove);
      _canvas.on.mouseOut.add(_canvas_mouseOut);
      _dragger.dragDelta.add(_onDrag);
  