Null check operator used on a null value

[xieyuhai]

#0 ChangeNotifier.notifyListeners (package:flutter/src/foundation/change_notifier.dart:218)

1 #1 ValueNotifier.value= (package:flutter/src/foundation/change_notifier.dart:292)
2 #2 _RenderEasyRefreshSliverLoad.performLayout (package:flutter_easyrefresh/src/footer/load_indicator.dart:183)
3 #3 RenderObject.layout (package:flutter/src/rendering/object.dart:1777)
4 #4 RenderSliverEdgeInsetsPadding.performLayout (package:flutter/src/rendering/sliver_padding.dart:132)
5 #5 RenderSliverPadding.performLayout (package:flutter/src/rendering/sliver_padding.dart:371)
6 #6 RenderObject.layout (package:flutter/src/rendering/object.dart:1777)
7 #7 RenderViewportBase.layoutChildSequence (package:flutter/src/rendering/viewport.dart:507)
8 #8 RenderViewport._attemptLayout (package:flutter/src/rendering/viewport.dart:1561)
9 #9 RenderViewport.performLayout (package:flutter/src/rendering/viewport.dart:1470)

[xuelongqy]

请使用v2.2.1

[xieyuhai]

好的，谢谢