private void put(ConfigCacheKey key, ConfigResponse config) {
        PayloadChecksum xxhash64 = config.getPayloadChecksums().getForType(XXHASH64);
        checksums.put(key, xxhash64);
        checksumToConfig.put(xxhash64, config);
    }
Cache that holds configs and config definitions (builtin and user config definitions).

@author vegardh
configserver/src/main/java/com/yahoo/vespa/config/server/ServerCache.java