if stringsHasPrefixFold(k, ReservedMetadataPrefixLower) {
			// Do not need to send any internal metadata
			// values to client.
			continue
		}

		// https://github.com/google/security-research/security/advisories/GHSA-76wf-9vgp-pj7w
		if equals(k, xhttp.AmzMetaUnencryptedContentLength, xhttp.AmzMetaUnencryptedContentMD5) {
			continue
		}

		var isSet bool
		for _, userMetadataPrefix := range userMetadataKeyPrefixes {