bitrotSumsTotalSize := ceilFrac(length, shardSize) * int64(h.Size()) // Size used for storing bitrot checksums.
			totalFileSize = bitrotSumsTotalSize + length
		}
		r.CloseWithError(disk.CreateFile(context.TODO(), origvolume, volume, filePath, totalFileSize, r))
	}()
	return bw
}

// ReadAt() implementation which verifies the bitrot hash available as part of the stream.
type streamingBitrotReader struct {