cleanPlugins abstract method Null safety

1. baguette
2. IPlugin
3. IPlugin
4. cleanPlugins abstract method

IPlugin class

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