code: public function dir_opendir($path, $options)
      {
          $this->blobs = $this->getStorageClient($path)->listBlobs(
              $this->getContainerName($path)
          );
          return is_array($this->blobs);
      }
docs: Attempt to open a directory
  
  @param  string $path
  @param  integer $options
  @return boolean