PayloadChecksum getResponseConfigXxhash64() {
        Inspector xxhash64Field = getResponseField(RESPONSE_CONFIG_XXHASH64);
        return xxhash64Field.valid()
                ? new PayloadChecksum(xxhash64Field.asString(), XXHASH64)
                : PayloadChecksum.empty(XXHASH64);
    }
Contains response data for a slime response and methods for decoding the response data that
are common to all {@link Slime} based config requests.

@author Ulf Lilleengen
config/src/main/java/com/yahoo/vespa/config/protocol/SlimeResponseData.java