onReady property Null safety

1. baguette
2. AtlasWidget
3. AtlasWidget
4. onReady property

AtlasWidget class

1. Constructors
2. AtlasWidget
3. Properties
4. allowRotate
5. allowScroll
6. allowUserLocation
7. allowUserLocationButton
8. allowZoom
9. background
10. hashCode
11. height
12. implyUserLocation
13. key
14. liteMode
15. location
16. markers
17. onIdle
18. onMove
19. onReady
20. runtimeType
21. width
22. Methods
23. createElement
24. createState
25. debugDescribeChildren
26. debugFillProperties
27. noSuchMethod
28. toDiagnosticsNode
29. toString
30. toStringDeep
31. toStringShallow
32. toStringShort
33. Operators
34. operator ==