anchor.diff:    }
   
     void run(fn) {
  +    time = html.window.performance.now();
  +
       _zone.run(() {
         flags |= tickRunningFlag;
   
  
positive.code:     if ((flags & framePendingFlag) == 0) {
        return;
      }
  
      _zone.run(() {
        flags &= ~framePendingFlag;
  
negative.code:   _WriteGroup _writeGroup;
  
    HeapPriorityQueue<_WriteGroup> _writeQueue =
    new HeapPriorityQueue<_WriteGroup>();
  
    Completer _readCompleter;
    Completer _afterCompleter;
  