NERoomChatTextMessage constructor Null safety

1. netease_roomkit
2. netease_roomkit
3. NERoomChatTextMessage
4. NERoomChatTextMessage constructor

NERoomChatTextMessage class

1. Constructors
2. NERoomChatTextMessage
3. Properties
4. fromNick
5. fromUserUuid
6. hashCode
7. messageType
8. messageUuid
9. runtimeType
10. text
11. time
12. toUserUuidList
13. Methods
14. noSuchMethod
15. toString
16. Operators
17. operator ==