shardSize:    shardSize,
		canClose:     &sync.WaitGroup{},
	}
	bw.canClose.Add(1)
	go func() {
		defer bw.canClose.Done()

		totalFileSize := int64(-1) // For compressed objects length will be unknown (represented by length=-1)
		if length != -1 {
			bitrotSumsTotalSize := ceilFrac(length, shardSize) * int64(h.Size()) // Size used for storing bitrot checksums.
			totalFileSize = bitrotSumsTotalSize + length
		}