code: public ConfigBuilder withMasterName(final String masterName) {
          if (masterName == null || "".equals(masterName)) {
              throw new IllegalArgumentException("masterName is null or empty: " + masterName);
          }
          this.masterName = masterName;
          return this;
      }
docs: Configs created by this ConfigBuilder will use the given Redis master name.
  
  @param masterName the Redis set of sentinels
  @return this ConfigBuilder