NotificationBuilder constructor Null safety

1. wings_data_model
2. wings_data_model
3. NotificationBuilder
4. NotificationBuilder constructor

NotificationBuilder class

1. Constructors
2. NotificationBuilder
3. Properties
4. category
5. dateTime
6. hashCode
7. id
8. name
9. read
10. runtimeType
11. Methods
12. noSuchMethod
13. replace
14. toString
15. update
16. Operators
17. operator ==