Files are stored in temporary folder until they're saved to a dedicated folder.
Inheritance: implements IteratorAggregate, implements Countable, implements Symfony\Component\Serializer\Normalizer\NormalizableInterface
 private function loadOutputFiles(OutputFileList $list, array $ids)
 {
     foreach ($ids as $format => $id) {
         $path = $this->getOutputFilePath($id);
         $list->get($format)->setPath($path)->setId($id);
     }
 }