Code review comment for lp:~vila/ubuntu-ci-services-itself/testy

Thanks for agreeing on the caller/callee semantics for passing of the test_request_id as the queue handle from the Lander to the Test Runner.

This MP looks good, I'll approve.

The questions you raise above merit their own MP. I'll hopefully get to a proposal by Monday morning. The general idea is to:
 - define the calling convention to pass the progress queue handle from the caller to the callee (as Andy described)
 - define progress semantics (what is the progress interval, what is considered a timeout, role of caller and callee)
 - define task queue semantics (role of the producer and consumer)