Consume messages on duplicate context

[juliantcook]

Describe the feature

Consume messages on a duplicate context regardless of whether Vert.x tracing is enabled so that a context's local data can be used amongst handlers.

Use cases

Users may want to have a context they can share between handlers for a single message, like the behaviour users are used to from HTTP request handlers.

Contribution

I can raise a PR for this if it is agreed it is useful and not detrimental.

If we don't want to add this behaviour can we update the docs to reflect: #213

Thanks!

[vietj]

I think we can schedule this contribution for 4.3.0