“ext.flutter.inspector.getRootWidgetSummaryTree”的回调

今天当我启动 flutter 2.0.x 应用程序时，显示错误：

======== Exception caught by Flutter framework =====================================================
The following _CastError was thrown during a service extension callback for "ext.flutter.inspector.getRootWidgetSummaryTree":
Null check operator used on a null value

When the exception was thrown, this was the stack: 
#0      WidgetInspectorService._registerObjectGroupServiceExtension.<anonymous closure> (package:flutter/src/widgets/widget_inspector.dart:793:84)
#1      WidgetInspectorService._registerObjectGroupServiceExtension.<anonymous closure> (package:flutter/src/widgets/widget_inspector.dart:792:17)
#2      BindingBase.registerServiceExtension.<anonymous closure> (package:flutter/src/foundation/binding.dart:597:32)
<asynchronous suspension>
====================================================================================================

似乎颤动框架错误。为什么会这样？关于这个的任何线索？是否可以修复它或避免此错误？