Do consume messages on the correct thread after resume

[hadadil]

Motivation:

In our code we do pause the consumer and later resume it. something as below

consumer.pause();
Uni<Void> processing = ....
processing
.eventually(consumer::resume)
.subscribe()
.with(UniHelper.NOOP);

when we call resume the next msg processed on event loop regardless the consumption meant to be on worker thread based on the Verticle deployment.
Conformance:

You should have signed the Eclipse Contributor Agreement as explained in https://github.com/eclipse/vert.x/blob/master/CONTRIBUTING.md
Please also make sure you adhere to the code style guidelines: https://github.com/vert-x3/wiki/wiki/Vert.x-code-style-guidelines

[hadadil]

I treid to sign this agreement, but during the registration I am getting

The website encountered an unexpected error. Try again later.

[vietj]

try again :-)