anchor.diff:    }) : super(key: key);
   
     final Widget child;
  -  final PerformanceView performance;
  +  final Performance performance;
   
     _BottomSheetState createState() => new _BottomSheetState();
   }
  
positive.code:           child: new CustomOneChildLayout(
              delegate: _layout,
              token: _layout.childTop.value,
              child: new Material(child: config.child)
            )
          );
        }
  
negative.code:           ),
            // sheet
            new _BottomSheet(
              performance: _performance,
              child: child
            )
          ])
  