public function load($resource, $type = null)
    {
        if (!preg_match('/^[^\:]+(?:::?(?:[^\:]+))?$/', $resource)) {
            throw new \InvalidArgumentException(sprintf('Invalid resource "%s" passed to the "service" route loader: use the format "service::method" or "service" if your service has an "__invoke" method.', $resource));
        }

        if (1 === substr_count($resource, ':')) {
            $resource = str_replace(':', '::', $resource);
            @trigger_error(sprintf('Referencing service route loaders with a single colon is deprecated since Symfony 4.1. Use %s instead.', $resource), E_USER_DEPRECATED);
        }

        $parts = explode('::', $resource);
        $serviceString = $parts[0];
        $method = $parts[1] ?? '__invoke';

        $loaderObject = $this->getServiceObject($serviceString);

        if (!\is_object($loaderObject)) {
            throw new \LogicException(sprintf('%s:getServiceObject() must return an object: %s returned', \get_class($this), \gettype($loaderObject)));
        }

        if (!\is_callable([$loaderObject, $method])) {
            throw new \BadMethodCallException(sprintf('Method "%s" not found on "%s" when importing routing resource "%s"', $method, \get_class($loaderObject), $resource));
        }

        $routeCollection = $loaderObject->$method($this);

        if (!$routeCollection instanceof RouteCollection) {
            $type = \is_object($routeCollection) ? \get_class($routeCollection) : \gettype($routeCollection);

            throw new \LogicException(sprintf('The %s::%s method must return a RouteCollection: %s returned', \get_class($loaderObject), $method, $type));
        }

        // make the service file tracked so that if it changes, the cache rebuilds
        $this->addClassResource(new \ReflectionClass($loaderObject), $routeCollection);

        return $routeCollection;
    }