Add long polling capability for HTTP store

[StephenOTT]

Add long polling capability for HTTP store

[cescoffier]

Do you have a use case? Do you know an HTTP config store that would do this? It would be very useful for testing.

[StephenOTT]

A use case I am looking at is scenarios where you are long polling a endpoint waiting for a data return: in my case it is camunda.org. Where you are long polling the camunda engine for "external tasks", where vertx is a worker. Since making this issue, camunda created their own http client wrapper with long polling abilities so the need is lessened on my side. But the generic use case still stands

[indiealexh]

If you want this for worker tasks, is this appropriate for the vertx-config module?
Surely this would be something you use web-client for to poll and pass work to your workers from there?