private function initLoaders()
    {
        $namespace = sprintf('%s\\ServiceLoader', __NAMESPACE__);
        $classes = ['MetadataCache', 'MetadataDrivers', 'MetadataFactory', 'Persisters', 'Rest', 'SearchClients'];

        foreach ($classes as $class) {
            $fqcn = sprintf('%s\\%s', $namespace, $class);
            $this->addLoader(new $fqcn);
        }
        return $this;
    }