role property Null safety

1. netease_roomkit
2. netease_roomkit
3. NERoomMember
4. role property

NERoomMember class

1. Constructors
2. NERoomMember
3. Properties
4. clientType
5. hashCode
6. isAudioOn
7. isInChatroom
8. isInRtcChannel
9. isSharingScreen
10. isSharingWhiteboard
11. isVideoOn
12. name
13. properties
14. role
15. runtimeType
16. uuid
17. Methods
18. noSuchMethod
19. toString
20. Operators
21. operator ==