求帮助，导入项目运行就会报错

[httpboy]

file:///D:/Environment/flutter_windows_v1.2.1-stable/flutter/packages/flutter/lib/src/widgets/navigator.dart:2091:9: Error: The getter 'SchedulerBinding' isn't defined for the class 'NavigatorState'.

• 'NavigatorState' is from 'package:flutter/src/widgets/navigator.dart' ('file:///D:/Environment/flutter_windows_v1.2.1-stable/flutter/packages/flutter/lib/src/widgets/navigator.dart').
  Try correcting the name to the name of an existing getter, or defining a getter or field named 'SchedulerBinding'.
  if (SchedulerBinding.instance.schedulerPhase == SchedulerPhase.idle) {

[liuxuleidota]

List<Route> get history => _history;
在这个文件里面加入这句,可能是你代码版本有点老?