PointerChange constructor Null safety

1. Flutter
2. dart:ui
3. PointerChange
4. PointerChange const constructor

PointerChange enum

1. Constructors
2. PointerChange
3. Values
4. cancel
5. add
6. remove
7. hover
8. down
9. move
10. up
11. panZoomStart
12. panZoomUpdate
13. panZoomEnd
14. Properties
15. hashCode
16. index
17. runtimeType
18. Methods
19. noSuchMethod
20. toString
21. Operators
22. operator ==
23. Constants
24. values