docs: def _WriteFileChunk(self, chunk):
      """Yields binary chunks, respecting archive file headers and footers.
  
      Args:
        chunk: the StreamedFileChunk to be written
      """
      if chunk.chunk_index == 0:
        # Make sure size of the original file is passed. It's required
        # when output_writer is StreamingTarWriter.
        st = os.stat_result((0o644, 0, 0, 0, 0, 0, chunk.total_size, 0, 0, 0))
        target_path = _ClientPathToString(chunk.client_path, prefix=self.prefix)
        yield self.archive_generator.WriteFileHeader(target_path, st=st)
  
      yield self.archive_generator.WriteFileChunk(chunk.data)
  
      if chunk.chunk_index == chunk.total_chunks - 1:
        yield self.archive_generator.WriteFileFooter()
        self.archived_files.add(chunk.client_path)