title: RabbitMQ: next message can be dequeued only after previous was acked
body: <p>I would like to have this constraint on a queue in RabbitMQ:</p>
  
  <p>Next message in the queue can't be dequeued before previous message (the one being processed) is acked. </p>
  
  <p>Through this I will achieve ordered processing of events and parallel processing across multiple queues. How do I/can I configure RabbitMQ for this?</p>
  
  <p>Edit (clarification): There will be many consumers all trying to get work from all the queues and since they can't get work from a queue that has an event being processed that isn't acked - ordered processing is maintained.</p>