getRootContext abstract method Null safety

1. baguette
2. IContextManager
3. IContextManager
4. getRootContext abstract method

IContextManager class

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