TestHarness<T extends ApplicationChannel> constructor Null safety

1. conduit_test
2. conduit_test
3. TestHarness<T extends ApplicationChannel>
4. TestHarness constructor

TestHarness class

1. Constructors
2. TestHarness
3. Properties
4. agent
5. application
6. channel
7. hashCode
8. options
9. runtimeType
10. Methods
11. afterStart
12. beforeStart
13. install
14. noSuchMethod
15. onSetUp
16. onTearDown
17. start
18. stop
19. toString
20. Operators
21. operator ==