private void sendOfflineMessage(JID recipient, OfflineMessage offlineMessage) {
        Element offlineInfo = offlineMessage.addChildElement("offline", NAMESPACE);
        offlineInfo.addElement("item").addAttribute("node",
                XMPPDateTimeFormat.format(offlineMessage.getCreationDate()));
        routingTable.routePacket(recipient, offlineMessage);
    }
Implements JEP-0013: Flexible Offline Message Retrieval. Allows users to request number of
messages, request message headers, retrieve specific messages, remove specific messages,
retrieve all messages and remove all messages.

@author Gaston Dombiak
xmppserver/src/main/java/org/jivesoftware/openfire/handler/IQOfflineMessagesHandler.java