OverlayState constructor Null safety

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

OverlayState class

1. Constructors
2. OverlayState
3. Properties
4. context
5. hashCode
6. mounted
7. runtimeType
8. widget
9. Methods
10. activate
11. build
12. createTicker
13. deactivate
14. debugFillProperties
15. debugIsVisible
16. didChangeDependencies
17. didUpdateWidget
18. dispose
19. initState
20. insert
21. insertAll
22. noSuchMethod
23. rearrange
24. reassemble
25. setState
26. toDiagnosticsNode
27. toString
28. toStringShort
29. Operators
30. operator ==