docs: @Override
    public void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {
      GcsFilename fileName = getFileName(req);
      if (SERVE_USING_BLOBSTORE_API) {
        BlobstoreService blobstoreService = BlobstoreServiceFactory.getBlobstoreService();
        BlobKey blobKey = blobstoreService.createGsBlobKey(
            "/gs/" + fileName.getBucketName() + "/" + fileName.getObjectName());
        blobstoreService.serve(blobKey, resp);
      } else {
        GcsInputChannel readChannel = gcsService.openPrefetchingReadChannel(fileName, 0, BUFFER_SIZE);
        copy(Channels.newInputStream(readChannel), resp.getOutputStream());
      }
    }