RouteInformationProvider constructor Null safety

1. Flutter
2. widgets
3. RouteInformationProvider
4. RouteInformationProvider constructor

RouteInformationProvider class

1. Constructors
2. RouteInformationProvider
3. Properties
4. hashCode
5. runtimeType
6. value
7. Methods
8. addListener
9. noSuchMethod
10. removeListener
11. routerReportsNewRouteInformation
12. toString
13. Operators
14. operator ==