n
 completed and all <code>CompletionListener</code> callbacks have returned before performing the commit or rollback.
 Incomplete sends should be allowed to complete normally unless an error occurs.

 <p>
 A <tt>CompletionListener</tt> callback method must not call <tt>close</tt> on its own <tt>Connection</tt>,
 <tt>Session</tt> or <tt>MessageProducer</tt> or call <tt>commit</tt> or <tt>rollback</tt> on its own
 <tt>Session</tt>. Doing so will cause the <tt>close</tt>, <tt>commit</tt> or <tt>rollback</tt> 