DraggableScrollableController constructor Null safety

1. Flutter
2. widgets
3. DraggableScrollableController
4. DraggableScrollableController constructor

DraggableScrollableController class

1. Constructors
2. DraggableScrollableController
3. Properties
4. hashCode
5. hasListeners
6. isAttached
7. pixels
8. runtimeType
9. size
10. Methods
11. addListener
12. animateTo
13. dispose
14. jumpTo
15. noSuchMethod
16. notifyListeners
17. pixelsToSize
18. removeListener
19. reset
20. sizeToPixels
21. toString
22. Operators
23. operator ==