public function visit(Notification $notification, Request $request): Request
    {
        $expiration = $notification->getExpiration();

        if ($expiration) {
            $request = $request->withHeader('apns-expiration', (string) $expiration->getValue());
        }

        return $request;
    }
public function visit(Notification $notification, Request $request): Request
    {
        $expiration = $notification->getExpiration();

        if ($expiration) {
            $request = $request->withHeader('apns-expiration', (string) $expiration->getValue());
        }

        return $request;
    }
{@inheritdoc}