1. Constructors
2. new
3. Properties
4. action
5. hashCode
6. icon
7. key
8. message
9. onClose
10. runtimeType
11. severity
12. showIcon
13. title
14. Methods
15. asFocusable ^(ext)
16. asSemanticButton ^(ext)
17. asSemanticHeading ^(ext)
18. build
19. createElement
20. debugDescribeChildren
21. debugFillProperties
22. excludeFromSemantics ^(ext)
23. mergeSemantics ^(ext)
24. noSuchMethod
25. toDiagnosticsNode
26. toString
27. toStringDeep
28. toStringShallow
29. toStringShort
30. withSemanticLabel ^(ext)
31. Operators
32. operator ==