code: func (gcs defaultGCSHandler) Fetch(c context.Context, i *Client, content isolateservice.HandlersEndpointsV1RetrievedContent, dest io.Writer) error {
  	rgen := func() (*http.Request, error) {
  		return http.NewRequest("GET", content.Url, nil)
  	}
  	handler := func(resp *http.Response) error {
  		defer resp.Body.Close()
  		decompressor, err := isolated.GetDecompressor(i.namespace, resp.Body)
  		if err != nil {
  			return err
  		}
  		defer decompressor.Close()
  		_, err = io.Copy(dest, decompressor)
  		return err
  	}
  	_, err := lhttp.NewRequest(c, i.authClient, i.retryFactory, rgen, handler, nil)()
  	return err
  }
docs: // Fetch uses the provided HandlersEndpointsV1RetrievedContent response to
  // download content from GCS to the provided dest.