public static PayloadChecksums from(String configMd5, String configXxhash64) {
        return new PayloadChecksums()
                .add(new PayloadChecksum(configMd5, MD5))
                .add(new PayloadChecksum(configXxhash64, XXHASH64));
    }
Checksums for config payload, typically 1 for each PayloadChecksum type (md5 and xxhash64).
Initialized with empty checksum for each existing type.

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