surface property Null safety

1. Flutter
2. material
3. ColorScheme
4. surface property

ColorScheme class

1. Constructors
2. ColorScheme
3. dark
4. fromSeed
5. fromSwatch
6. highContrastDark
7. highContrastLight
8. light
9. Properties
10. background
11. brightness
12. error
13. errorContainer
14. hashCode
15. inversePrimary
16. inverseSurface
17. onBackground
18. onError
19. onErrorContainer
20. onInverseSurface
21. onPrimary
22. onPrimaryContainer
23. onSecondary
24. onSecondaryContainer
25. onSurface
26. onSurfaceVariant
27. onTertiary
28. onTertiaryContainer
29. outline
30. outlineVariant
31. primary
32. primaryContainer
33. primaryVariant
34. runtimeType
35. scrim
36. secondary
37. secondaryContainer
38. secondaryVariant
39. shadow
40. surface
41. surfaceTint
42. surfaceVariant
43. tertiary
44. tertiaryContainer
45. Methods
46. copyWith
47. debugFillProperties
48. noSuchMethod
49. toDiagnosticsNode
50. toString
51. toStringShort
52. Operators
53. operator ==
54. Static methods
55. lerp