requestData method Null safety

1. Flutter
2. dart:html
3. MediaRecorder
4. requestData method

MediaRecorder class

1. Constructors
2. MediaRecorder
3. Properties
4. audioBitsPerSecond
5. hashCode
6. mimeType
7. on
8. onError
9. onPause
10. runtimeType
11. state
12. stream
13. videoBitsPerSecond
14. Methods
15. addEventListener
16. dispatchEvent
17. noSuchMethod
18. pause
19. removeEventListener
20. requestData
21. resume
22. start
23. stop
24. toString
25. Operators
26. operator ==
27. Static methods
28. isTypeSupported
29. Constants
30. errorEvent
31. pauseEvent