docs: protected static Map<String, WriteToText.FieldFn<KV<String, Integer>>>
        configureOutput() {
      Map<String, WriteToText.FieldFn<KV<String, Integer>>> config = new HashMap<>();
      config.put("user", (c, w) -> c.element().getKey());
      config.put("total_score", (c, w) -> c.element().getValue());
      return config;
    }