// since the specified time otherwise return 412 (precondition failed).
	ifModifiedSinceHeader := r.Header.Get(xhttp.AmzCopySourceIfModifiedSince)
	if ifModifiedSinceHeader != "" {
		if givenTime, err := amztime.ParseHeader(ifModifiedSinceHeader); err == nil {
			if !ifModifiedSince(objInfo.ModTime, givenTime) {
				// If the object is not modified since the specified time.
				writeHeaders()

			return restoreObjStatus{}, errRestoreHDRMalformed
		}
		if strings.TrimSpace(expiryTokens[0]) != "expiry-date" {
			return restoreObjStatus{}, errRestoreHDRMalformed
		}
		expiry, err := amztime.ParseHeader(strings.Trim(expiryTokens[1], `"`))
		if err != nil {
			return restoreObjStatus{}, errRestoreHDRMalformed
		}
		return completedRestoreObj(expiry), nil
	}
	return restoreObjStatus{}, errRestoreHDRMalformed