code: @Override
    public List<? extends OutputWriter<ByteBuffer>> createWriters(int numShards) {
      ImmutableList.Builder<SizeSegmentingGoogleCloudStorageFileWriter> result =
          new ImmutableList.Builder<>();
      for (int i = 0; i < numShards; ++i) {
        result.add(new SizeSegmentingGoogleCloudStorageFileWriter(bucket, fileNamePattern, i,
            mimeType, segmentSizeLimit));
      }
      return result.build();
    }
docs: Returns {@link OutputWriter}s that write files to GCS but segments the files based on the
  maximum allowed file size. One writer can write more than one file per shard