public static void availableSession(ClientSession session, Presence presence) {
        if (!listeners.isEmpty()) {
            for (PresenceEventListener listener : listeners) {
                try {
                    listener.availableSession(session, presence);
                } catch (Exception e) {
                    Log.warn("An exception occurred while dispatching a 'availableSession' event!", e);
                }
            }
        }
    }
Notification message indicating that a session that was not available is now
available. A session becomes available when an available presence is received.
Sessions that are available will have a route in the routing table thus becoming
eligible for receiving messages (in particular messages sent to the user bare JID).

@param session the session that is now available.
@param presence the received available presence.
xmppserver/src/main/java/org/jivesoftware/openfire/user/PresenceEventDispatcher.java