Nats\Connection::handleMSG PHP Method

    private function handleMSG($line)
    {
        $parts = explode(' ', $line);
        $subject = null;
        $length = trim($parts[3]);
        $sid = $parts[2];
        if (count($parts) == 5) {
            $length = trim($parts[4]);
            $subject = $parts[3];
        } elseif (count($parts) == 4) {
            $length = trim($parts[3]);
            $subject = $parts[1];
        }
        $payload = $this->receive($length);
        $msg = new Message($subject, $payload, $sid, $this);
        if (!isset($this->subscriptions[$sid])) {
            throw new Exception('subscription not found');
        }
        $func = $this->subscriptions[$sid];
        if (is_callable($func)) {
            $func($msg);
        } else {
            throw new Exception('not callable');
        }
        return;
    }