code: public ConfigBuilder withHost(final String host) {
          if (host == null || "".equals(host)) {
              throw new IllegalArgumentException("host must not be null or empty: " + host);
          }
          this.host = host;
          return this;
      }
docs: Configs created by this ConfigBuilder will have the given Redis hostname.
  
  @param host the Redis hostname
  @return this ConfigBuilder