anchor.diff:      // do event times extend slightly beyond the times we get from frame start
       // and end flow events.
   
  -    // Epsilon in microseconds.
  -    const int epsilon = 50;
  +    // Epsilon in microseconds. If more than half of the event fits in bounds,
  +    // then we consider the event as fitting. If the event has a large duration,
  +    // consider it as fitting if it fits within 500 micros of the frame bound.
  +    final int epsilon = min(e.duration ~/ 2, 500);
   
       // Allow the event to extend the frame boundaries by [epsilon] microseconds.
       final bool fitsStartBoundary = f.startTime - e.startTime - epsilon < 0;
  
positive.code:   bool _maybeAddEventToFrame(TimelineEvent event, TimelineFrame frame) {
      assert(frame.isWellFormed);
  
      // TODO(kenzie): consider trimming VSYNC layer from pipelineProduceFlow. It
      // can start outside of the frame's time boundaries and could pose a risk
      // for us missing a frame.
  
      // Ensure the event fits within the frame's time boundaries.
      if (!_eventOccursWithinFrameBoundaries(event, frame)) {
        return false;
  
negative.code:   void _maybeAddCompletedFrame(TimelineFrame frame) {
      if (frame.isReadyForTimeline && frame.addedToTimeline == null) {
        _frameCompleteController.add(frame);
        _pendingFrames.remove(frame.id);
        frame.addedToTimeline = true;
      }
    }
  