Incorrect handling of Hub.Publish results

[Simon Richardson]

We don't always correctly handle the results from Hub.Publish. We should review each on a case-by-case basis.

The done channel in our pubsub implementation ensures that all callbacks are completed before returning as completed. For fire and forget calls it would be advantageous to leave as ignored, but for other calls where we want to ensure that a piece of logic has been performed/setup before moving on, will lead to a logic race. Those cases need to understood in a wider context and correctly fixed.