Description

Messages sent to offline users is published in PubSub node, from where that message is sent to all the node subscribers as a PubSub notification.

<message from='pubsub.coffeebean.local' to='bard@shakespeare.lit' id='foo'>
  <event xmlns='http://jabber.org/protocol/pubsub#event'>
    <items node='message_sink'>
      <item id='ae890ac52d0df67ed7cfdf51b644e901'>
        <message type="chat" xmlns="jabber:client" id="x2ps6u0004"
          to="userB_h6x1bt0002@coffeebean.local"
          from="userA_uyhx8p0001@coffeebean.local/1149352695-tigase-20">
          <body>Hello</body>
        </message>
      </item>
    </items>
  </event>
</message>