MockServer<T> constructor Null safety

1. conduit_test
2. conduit_test
3. MockServer<T>
4. MockServer constructor

MockServer class

1. Constructors
2. MockServer
3. Properties
4. hashCode
5. isEmpty
6. runtimeType
7. Methods
8. add
9. clear
10. close
11. next
12. noSuchMethod
13. open
14. toString
15. Operators
16. operator ==