func mustGetUUID() string {
	u, err := uuid.NewRandom()
	if err != nil {
		logger.CriticalIf(GlobalContext, err)
	}

	return u.String()
}

// mustGetUUIDBytes - get a random UUID as 16 bytes unencoded.
func mustGetUUIDBytes() []byte {
	u, err := uuid.NewRandom()
	if err != nil {
		logger.CriticalIf(GlobalContext, err)
	}
	return u[:]
}

	// for server that is started with `--no-compat`.
	if !etag.ContentMD5Requested(r.Header) && (crypto.S3KMS.IsEncrypted(mi.UserDefined) || crypto.SSEC.IsRequested(r.Header) || !globalServerCtxt.StrictS3Compat) {
		forceMD5 = mustGetUUIDBytes()
	}

	hashReader, err := hash.NewReaderWithOpts(ctx, reader, hash.Options{
		Size:       size,
		MD5Hex:     md5hex,
		SHA256Hex:  sha256hex,
		ActualSize: actualSize,
		DisableMD5: false,

	kind, _ := crypto.IsRequested(formValues)
	if !etag.ContentMD5Requested(formValues) && (kind == crypto.SSEC || kind == crypto.S3KMS || !globalServerCtxt.StrictS3Compat) {
		forceMD5 = mustGetUUIDBytes()
	}

	hashReader, err := hash.NewReaderWithOpts(ctx, reader, hash.Options{
		Size:       actualSize,
		MD5Hex:     clientETag.String(),
		SHA256Hex:  "",
		ActualSize: actualSize,

	// for server that is started with `--no-compat`.
	if !etag.ContentMD5Requested(r.Header) && (crypto.S3KMS.IsRequested(r.Header) || crypto.SSEC.IsRequested(r.Header) || !globalServerCtxt.StrictS3Compat) {
		forceMD5 = mustGetUUIDBytes()
	}
	hashReader, err := hash.NewReaderWithOpts(ctx, reader, hash.Options{
		Size:       size,
		MD5Hex:     md5hex,
		SHA256Hex:  sha256hex,
		ActualSize: actualSize,
		DisableMD5: false,