anchor.diff:    bool get isRunning => ((flags & runningFlags) != 0);
     bool get isFrameRunning => ((flags & frameRunningFlag) != 0);
   
  -  Queue<Function> _currentTasks = new Queue<Function>();
  +  final _TaskQueue _currentTasks = new _TaskQueue();
   
     ZoneSpecification _zoneSpec;
     Zone _zone;
  
positive.code: library uix.src.scheduler;
  
  import 'dart:async';
  import 'dart:collection';
  import 'dart:html' as html;
  import 'package:collection/priority_queue.dart';
  
  /// Write groups sorted by priority.
  ///
  
negative.code:     }
    }
  
    void _requestAnimationFrame() {
      if ((flags & framePendingFlag) == 0) {
        html.window.requestAnimationFrame(_handleAnimationFrame);
  