public boolean isEmpty() {
        switch (type) {
            case MD5: return this.equals(empty(MD5));
            case XXHASH64: return this.equals(empty(XXHASH64));
            default: throw new IllegalArgumentException("Unknown type " + type);
        }
    }
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