code: public ArmeriaRetrofitBuilder withClientOptions(
              BiFunction<String, ? super ClientOptionsBuilder, ClientOptionsBuilder> configurator) {
          this.configurator = requireNonNull(configurator, "configurator");
          return this;
      }
docs: Sets the {@link BiFunction} that is applied to the underlying {@link HttpClient}.
  
  @param configurator a {@link BiFunction} whose first argument is the the URI of the server endpoint and
  whose second argument is the {@link ClientOptionsBuilder} with default options of
  the new derived client