RouteTransitionRecord constructor Null safety

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

RouteTransitionRecord class

1. Constructors
2. RouteTransitionRecord
3. Properties
4. hashCode
5. isWaitingForEnteringDecision
6. isWaitingForExitingDecision
7. route
8. runtimeType
9. Methods
10. markForAdd
11. markForComplete
12. markForPop
13. markForPush
14. markForRemove
15. noSuchMethod
16. toString
17. Operators
18. operator ==