CommandManager constructor Null safety

1. sendbird_sdk
2. command_manager
3. CommandManager
4. CommandManager constructor

CommandManager class

1. Constructors
2. CommandManager
3. Properties
4. appState
5. cmdManager
6. eventManager
7. hashCode
8. runtimeType
9. sdk
10. webSocket
11. Methods
12. cleanUp
13. clearCompleters
14. noSuchMethod
15. processCommand
16. send
17. sendCommand
18. toString
19. Operators
20. operator ==