if err != nil {
		t.Fatal(err)
	}
	_, err = writer.Write([]byte("aaaaa"))
	if err != nil {
		t.Fatal(err)
	}
	if bw, ok := writer.(io.Closer); ok {
		bw.Close()
	}

	reader := newBitrotReader(disk, nil, volume, filePath, 35, bitrotAlgo, bitrotWriterSum(writer), 10)
	b := make([]byte, 10)
	if _, err = reader.ReadAt(b, 0); err != nil {
		t.Fatal(err)
	}
	if _, err = reader.ReadAt(b, 10); err != nil {

	if algo == HighwayHash256S {
		return newStreamingBitrotWriter(disk, origvolume, volume, filePath, length, algo, shardSize)
	}
	return newWholeBitrotWriter(disk, volume, filePath, algo, shardSize)
}

func newBitrotReader(disk StorageAPI, data []byte, bucket string, filePath string, tillOffset int64, algo BitrotAlgorithm, sum []byte, shardSize int64) io.ReaderAt {
	if algo == HighwayHash256S {

		partsMetadata[i] = cleanFileInfo(latestMeta)
	}

	// source data dir shall be empty in case of XLV1
	// differentiate it with dstDataDir for readability
	// srcDataDir is the one used with newBitrotReader()
	// to read existing content.
	srcDataDir := latestMeta.DataDir
	dstDataDir := latestMeta.DataDir
	if latestMeta.XLV1 {
		dstDataDir = migrateDataDir
	}

	var inlineBuffers []*bytes.Buffer