anchor.diff:          name: 'repaintRainbow',
           getter: () => debugRepaintRainbowEnabled,
           setter: (bool value) {
  +          bool repaint = debugRepaintRainbowEnabled && !value;
             debugRepaintRainbowEnabled = value;
  +          if (repaint)
  +            _forceRepaint();
           }
         );
         return true;
  
positive.code:     renderView.hitTest(result, position: position);
      super.hitTest(result, position);
    }
  }
  
  /// Prints a textual representation of the entire render tree.
  
negative.code:           if (debugPaintSizeEnabled == value)
              return;
            debugPaintSizeEnabled = value;
            _forceRepaint();
          }
        );
        return true;
  