gcs_file->buffer.resize(0);
        return -1;
      }
      size_t remaining_copy =
          (std::min)(n - copy_size, gcs_file->buffer.size());
      memcpy(buffer + copy_size, gcs_file->buffer.data(), remaining_copy);
      copy_size += remaining_copy;
    }
    if (copy_size < n) {
      // Forget the end-of-file flag to allow for clients that poll on the