onDispose method Null safety

1. baguette
2. ViewModel
3. ViewModel
4. onDispose method

ViewModel class

1. Constructors
2. ViewModel
3. Properties
4. hashCode
5. runtimeType
6. Methods
7. getModel
8. noSuchMethod
9. onCreate
10. onDispose
11. setModel
12. toString
13. Operators
14. operator ==