NotificationsManager constructor Null safety

1. baguette
2. NotificationsManager
3. NotificationsManager
4. NotificationsManager constructor

NotificationsManager class

1. Constructors
2. NotificationsManager
3. Properties
4. hashCode
5. runtimeType
6. Methods
7. addPlugin
8. cleanPlugins
9. getPlugin
10. noSuchMethod
11. removePlugin
12. toString
13. Operators
14. operator ==