anchor.diff:  
     void _fireMarkerEvent(List<MarkerDelta> deltas) {
       if (_markersPauseCount == 0) {
  -      _markerController.add(new MarkerChangeEvent.fromList(deltas));
  +      _markerController.add(new MarkerChangeEvent(deltas));
       } else {
         _makerChangeList.addAll(deltas);
       }
  
positive.code:   void resumeMarkerStream() {
      _markersPauseCount--;
      if (_markersPauseCount == 0 && _makerChangeList.isNotEmpty) {
        _markerController.add(new MarkerChangeEvent.fromList(_makerChangeList));
        _makerChangeList.clear();
      }
    }
  
negative.code: 
    List<MarkerDelta> changes;
  
    MarkerChangeEvent(List<MarkerDelta> delta): changes = new UnmodifiableListView(delta);
  
    /**
     * Checks if given [Resource] is present in the list of delta for marker changes
  