private Properties config(final Properties config) {
    if (replaceConfig) {
      return config;
    }
    Properties allConfig = getDistributedSystemProperties();
    allConfig.putAll(this.config);
    allConfig.putAll(config);
    return allConfig;
  }
Use {@code Builder} for more options in constructing {@code CacheRule}.

@return a new {@code Builder}
geode-dunit/src/main/java/org/apache/geode/test/dunit/rules/CacheRule.java