Support long/infinite polling (streamed / chunked content)

[micoq]

Some REST APIs provides streamed content: the HTTP client connects once and stay connected and the server pushes content to the client as it becomes available chunk per chunk.

Here is an example with Icinga: https://www.icinga.com/docs/icinga2/latest/doc/12-icinga2-api/#event-streams
This API will send the monitoring events as they occur.

Currently, the http_poller plugin will wait for the whole content and never returns an event object:

private
def handle_success(queue, name, request, response, execution_time)
  body = response.body # Wait for the whole content to be received
  [...] # Decode and create the event object
end

It could be nice to support this type of long polling. I know the manticore library could handle that like this for a single connection:

private
  def handle_success(queue, name, request, response, execution_time)
  response.body do |chunk|
      [...] # Decode and create the event object
  end
end

(however it's not enough since the loop will be blocked indefinitely and the other requests will never be triggered)