Revert moving ActivateDispatchers to worker Execute

[trevorr]

Fixes #161 by moving ActivateDispatchers back to HandleOKCallback. We're using this fix on a fork, and have verified that it fixes the hang.

[confluent-cla-assistant]

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✅ trevorr
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[milindl]

Thanks for the PR @trevorr , but this will make the oauthbearer tests fail (as the connection requires the dispatchers to be active in that case).

I was working on a PR for this already. It's still not finished, but I cleaned it up a little and raised it as #190 , as I realized you might want to verify if that works for you. I tested with a similar assertion added about the threads as present in the original issue, and with further tests I did.

[trevorr]

It's great to hear there's a PR in progress. I just wanted to share what we're using for now as a straw man proposal. I'll go ahead and close this since you have a fix on the way.