anchor.diff:                      ),
                     ),
                   ),
  -              ),
  -          ],
  -        ),
  -      );
  +            ],
  +          ),
  +        );
  +      },
  +    );
  +  }
   
     double _cacheExtent(BoxConstraints constraints) => max(
           constraints.maxHeight * _screenScrollCount,
  
positive.code:                         controller: frontScrollController,
                          scrollDirection: widget.scrollDirection,
                          reverse: widget.reverse,
                          cacheExtent: _cacheExtent(constraints),
                          alignment: frontAlignment,
                          physics: widget.physics,
                          addSemanticIndexes: widget.addSemanticIndexes,
  
negative.code:                         itemPositionsNotifier: backItemPositionsNotifier,
                          scrollDirection: widget.scrollDirection,
                          reverse: widget.reverse,
                          cacheExtent: cacheExtent,
                          alignment: backAlignment,
                          physics: widget.physics,
                          addSemanticIndexes: widget.addSemanticIndexes,
  