private function stubBinder($iterator, $return, $files, $time)
 {
     $this->binder->set($iterator, $return);
     $this->binder->setFiles($files);
     $this->binder->setLastModified($time);
     $this->binder->setMimeType('text/css');
 }
 private function stubBinder($return)
 {
     $files = new FileList([]);
     $this->binder->set($files, $return);
     return $files;
 }