data property Null safety

1. baguette
2. ScreenWidget
3. ScreenWidget
4. data property

ScreenWidget class

1. Constructors
2. ScreenWidget
3. Properties
4. data
5. hashCode
6. key
7. runtimeType
8. Methods
9. createElement
10. createState
11. debugDescribeChildren
12. debugFillProperties
13. getName
14. noSuchMethod
15. toDiagnosticsNode
16. toString
17. toStringDeep
18. toStringShallow
19. toStringShort
20. Operators
21. operator ==