RTCRoom constructor Null safety

1. volc_engine_rtc
2. bytertc_room_api
3. RTCRoom
4. RTCRoom constructor

RTCRoom class

1. Constructors
2. RTCRoom
3. Properties
4. hashCode
5. rangeAudio
6. roomId
7. runtimeType
8. spatialAudio
9. Methods
10. destroy
11. joinRoom
12. leaveRoom
13. noSuchMethod
14. pauseAllSubscribedStream
15. pauseForwardStreamToAllRooms
16. publishScreen
17. publishStream
18. resumeAllSubscribedStream
19. resumeForwardStreamToAllRooms
20. sendRoomBinaryMessage
21. sendRoomMessage
22. sendUserBinaryMessage
23. sendUserMessage
24. setMultiDeviceAVSync
25. setRemoteVideoConfig
26. setRTCRoomEventHandler
27. setUserVisibility
28. startForwardStreamToRooms
29. stopForwardStreamToRooms
30. subscribeScreen
31. subscribeStream
32. toString
33. unpublishScreen
34. unpublishStream
35. unsubscribeScreen
36. unsubscribeStream
37. updateForwardStreamToRooms
38. updateToken
39. Operators
40. operator ==