protected function handleMessage($message)
    {
        $handler = $this->messageHandler;

        if (!is_callable($handler)) {
            Log::debug('No handler enabled.');

            return null;
        }

        Log::debug('Message detail:', $message->all());

        $type = $this->messageTypeMapping[ $message->get('InfoType') ];

        $response = null;

        if ($type) {
            $response = call_user_func_array($handler, [$message]);
        }

        return $response;
    }