dirty property Null safety

1. sendbird_sdk
2. typing_status
3. TypingStatus
4. dirty property

TypingStatus class

1. Constructors
2. TypingStatus
3. Properties
4. channelType
5. channelUrl
6. dirty
7. hashCode
8. key
9. primaryKey
10. runtimeType
11. timestamp
12. user
13. Methods
14. copyWith
15. noSuchMethod
16. toString
17. Operators
18. operator ==