backgroundColor property Null safety

1. baguette
2. AvatarWidget
3. AvatarWidget
4. backgroundColor property

AvatarWidget class

1. Constructors
2. AvatarWidget
3. Properties
4. backgroundColor
5. foregroundColor
6. hashCode
7. image
8. key
9. margin
10. mode
11. padding
12. runtimeType
13. size
14. Methods
15. build
16. createElement
17. debugDescribeChildren
18. debugFillProperties
19. noSuchMethod
20. toDiagnosticsNode
21. toString
22. toStringDeep
23. toStringShallow
24. toStringShort
25. Operators
26. operator ==