bp := copy(nb, b)
	for bp < n {
		chunk := min(bp, chunkMax)
		bp += copy(nb[bp:], nb[:chunk])
	}
	return nb
}

// ToUpper returns a copy of the byte slice s with all Unicode letters mapped to
// their upper case.
func ToUpper(s []byte) []byte {
	isASCII, hasLower := true, false
	for i := 0; i < len(s); i++ {
		c := s[i]
		if c >= utf8.RuneSelf {
			isASCII = false
			break
		}

		MTime:     opts.MTime,
		VersionID: opts.VersionID,
		EvalMetadataFn: func(oi *ObjectInfo, gerr error) (ReplicateDecision, error) {
			oi.UserDefined[strings.ToLower(xhttp.AmzObjectLockLegalHold)] = strings.ToUpper(string(legalHold.Status))
			oi.UserDefined[ReservedMetadataPrefixLower+ObjectLockLegalHoldTimestamp] = UTCNow().Format(time.RFC3339Nano)