getTaskInfo method Null safety

1. smh_flutter_sdk
2. smh_task
3. SMHTask<T>
4. getTaskInfo abstract method

SMHTask class

1. Constructors
2. SMHTask
3. Properties
4. confirmKeyCalBack
5. currentQueue
6. finishCalBack
7. hashCode
8. isolate
9. onReceiveProgress
10. onSendProgress
11. priority
12. receivePort
13. runtimeType
14. stateStream
15. taskId
16. Methods
17. cancel
18. createIsolate
19. dispose
20. finish
21. getTaskInfo
22. noSuchMethod
23. pause
24. resume
25. start
26. toString
27. Operators
28. operator ==