Add comments, clean up, and increase coverage. (#6290)
Add comments, clean up, and increase coverage. (#6290)

* Add comments, clean up, and increase coverage.

* Add TestCancelIngressProbing.
* Add more tests for pkg/network.go
* Rename 'ia' to better 'ing', since we no longer have IngressAccessor.

* Address nits.

* Better test error messages.

* Simplify messages, more clean up.

* Properly close channel.

knative-sandbox/net-istio,knative-sandbox/net-istio