BackgroundFetchRegistration class

1. Properties
2. downloaded
3. downloadTotal
4. id
5. title
6. totalDownloadSize
7. uploaded
8. uploadTotal
9. hashCode
10. on
11. runtimeType
12. Methods
13. abort
14. addEventListener
15. dispatchEvent
16. noSuchMethod
17. removeEventListener
18. toString
19. Operators
20. operator ==