anchor.diff:  }
   
   class FutureImage extends StatefulComponent {
  -  FutureImage({ this.image, this.size });
  +  FutureImage({ String key, this.image, this.size }) : super(key: key);
   
     Future<sky.Image> image;
     Size size;
  +
     sky.Image _resolvedImage;
  -
  -  void didMount() {
  -    super.didMount();
  -    _resolveImage();
  -  }
   
     void _resolveImage() {
       image.then((sky.Image resolvedImage) {
  
positive.code: }
  
  class AssetImage extends Component {
    AssetImage({ this.bundle, String name, this.size })
      : name = name, super(key: name);
  
    final AssetBundle bundle;
    final String name;
    final Size size;
  
    Widget build() {
  
negative.code:     });
    }
  
    void didMount() {
      super.didMount();
      _resolveImage();
    }
  
    void syncFields(FutureImage source) {
      bool needToResolveImage = (image != source.image);
      image = source.image;
  