NERtcVideoFrameRate constructor Null safety

1. netease_roomkit
2. netease_roomkit
3. NERtcVideoFrameRate
4. NERtcVideoFrameRate constructor

NERtcVideoFrameRate class

1. Constructors
2. NERtcVideoFrameRate
3. Properties
4. hashCode
5. runtimeType
6. Methods
7. noSuchMethod
8. toString
9. Operators
10. operator ==
11. Constants
12. fps_7
13. fps_10
14. fps_15
15. fps_24
16. fps_30