NERtcAudioDeviceType constructor Null safety

1. netease_roomkit
2. netease_roomkit
3. NERtcAudioDeviceType
4. NERtcAudioDeviceType constructor

NERtcAudioDeviceType class

1. Constructors
2. NERtcAudioDeviceType
3. Properties
4. hashCode
5. runtimeType
6. Methods
7. noSuchMethod
8. toString
9. Operators
10. operator ==
11. Constants
12. playout
13. record