// See https://golang.org/issue/22735
	/*
		// Write the sparse map and setup the sparse writer if necessary.
		if len(spd) > 0 {
			// Use tw.curr since the sparse map is accounted for in hdr.Size.
			if _, err := tw.curr.Write(spb); err != nil {
				return err
			}
			tw.curr = &sparseFileWriter{tw.curr, spd, 0}
		}
	*/
	return nil
}