@Override
    public String getHostName() throws UnknownHostException {
        Connection connection = conn;
        if (connection == null) {
            throw new UnknownHostException("Detached session");
        }
        return connection.getHostName();
    }
Returns a text with the available stream features. Each subclass may return different
values depending whether the session has been authenticated or not.

@return a text with the available stream features or {@code null} to add nothing.
xmppserver/src/main/java/org/jivesoftware/openfire/session/LocalSession.java