anchor.diff:        physicalHeight,
         sceneToken.value
       );
  -    Timeline.finishSync();
     }
   
     @override
  
positive.code: 
    @override
    void addToScene(ui.SceneBuilder builder, Offset layerOffset) {
      Timeline.startSync('ShaderMaskLayer::addToScene');
      builder.pushShaderMask(shader, maskRect.shift(layerOffset), transferMode);
      addChildrenToScene(builder, layerOffset);
      builder.pop();
      Timeline.finishSync();
    }
  
    @override
  
negative.code: // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  import 'dart:ui' as ui show ImageFilter, Picture, SceneBuilder;
  import 'dart:ui' show Offset;
  
  