anchor.diff:    Offset? _finalDropPosition;
     MultiDragGestureRecognizer? _recognizer;
     int? _recognizerPointer;
  -  bool _autoScrolling = false;
     // To implement the gap for the dragged item, we replace the dragged item
     // with a zero sized box, and then translate all of the later items down
     // by the size of the dragged item. This allows us to keep the order of the
  
positive.code:       );
      }
      return SliverList(delegate: childrenDelegate);
    }
  }
  
  
negative.code:     setState(() {
        _overlayEntry?.markNeedsBuild();
        _dragUpdateItems();
        _autoScroller?.startAutoScrollIfNecessary(_dragTargetRect);
      });
    }
  
  