code: @Override public XGBoostModel createImpl() {
      XGBoostV3.XGBoostParametersV3 p = this.parameters;
      XGBoostModel.XGBoostParameters parms = p.createImpl();
      return new XGBoostModel(model_id.key(), parms, new XGBoostOutput(null), null, null);
    }
docs: Version&Schema-specific filling into the impl