SMHMessageReadState constructor Null safety

1. smh_flutter_sdk
2. smh_string_enum
3. SMHMessageReadState
4. SMHMessageReadState const constructor

SMHMessageReadState enum

1. Constructors
2. SMHMessageReadState
3. Values
4. all
5. read
6. unRead
7. Properties
8. hashCode
9. index
10. runtimeType
11. Methods
12. noSuchMethod
13. toString
14. Operators
15. operator ==
16. Constants
17. values