title: When message will be erased from queue?
body: <p>Let's suppose we have one producer, one queue and some consumers which are subscribed on queue.</p>
  
  <pre><code>Producer -&gt; Queue -&gt; Consumers
  </code></pre>
  
  <p>Queues contains messages about life events. These messages should receive all consumers.</p>
  
  <p><strong>When queue will be erased?</strong> </p>
  
  <ol>
  <li>When all consumers get message?</li>
  <li>Or when one of consumers confirm message with flag ack (true)?</li>
  </ol>
  
  <p>And how to manage priority, who from consumers must to get message <strong>first/last</strong> (don't confuse with message priority).</p>
  
  <p>As instance I have 10 consumers and I want that the fifth consumer get message first,  remaining consumers later after specified time.</p>