@Override
    void createSession(String serverName, XmlPullParser xpp, Connection connection) throws XmlPullParserException {
        String currentStreamId = xpp.getAttributeValue("", "id");
        session = createLocalOutgoingServerSession(currentStreamId,  connection);
    }
Transfer an existing connection to a new session when a new streamID is detected. Also transfers existing
authentication method if previously set.
@param newStreamId new stream ID for the new session
@param existingAuthMethod authentication method used previously (possibly null)
xmppserver/src/main/java/org/jivesoftware/openfire/net/RespondingServerStanzaHandler.java