public function send(Message $message) : void
    {
        header('Content-Type: text/xml', true);

        $xml = $this->getOutputToSend($message);
        if ($xml !== false) {
            Utils::getContainer()->debugMessage($xml, 'out');
            echo $xml;
        }

        // DOMDocument::saveXML() returned false. Something is seriously wrong here. Not much we can do.
        exit(0);
    }