NotificationsKey constructor Null safety

1. baguette
2. NotificationsKey
3. NotificationsKey
4. NotificationsKey constructor

NotificationsKey class

1. Constructors
2. NotificationsKey
3. Properties
4. hashCode
5. runtimeType
6. Methods
7. noSuchMethod
8. toString
9. Operators
10. operator ==
11. Constants
12. RECEIVE_MESSAGE
13. TAG