private static PayloadChecksum fromMd5Data(AbstractUtf8Array data) {
        return new PayloadChecksum(ConfigUtils.getMd5(data), MD5);
    }
Checksums of config definition payload or config payload,
md5 and xxhash64 are the supported types at the moment.

@author hmusum
config/src/main/java/com/yahoo/vespa/config/PayloadChecksum.java