livePorts property Null safety

1. Flutter
2. vm_service
3. Isolate
4. livePorts property

Isolate class

1. Constructors
2. Isolate
3. Properties
4. breakpoints
5. error
6. exceptionPauseMode
7. extensionRPCs
8. hashCode
9. id
10. isolateFlags
11. isSystemIsolate
12. json
13. libraries
14. livePorts
15. name
16. number
17. pauseEvent
18. pauseOnExit
19. rootLib
20. runnable
21. runtimeType
22. startTime
23. type
24. Methods
25. noSuchMethod
26. toJson
27. toString
28. Operators
29. operator ==
30. Static methods
31. parse