public function composingStart($to)
    {
        $message = new \sb\XMPP\Message();

        $message->setTo($to);
        $message->setFrom($this->jid);
        $message->setType('chat');
        $node = $message->createElement('composing');
        $attr = $message->createAttribute('xmlns');
        $node->appendChild($attr);
        $attr->appendChild($message->createTextNode('http://jabber.org/protocol/chatstates'));

        $message->doc->appendChild($node);

        $this->sendMessage($message);
    }