IHttpManager constructor Null safety

1. baguette
2. IHttpManager
3. IHttpManager
4. IHttpManager constructor

IHttpManager class

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