如何使用PredictXGBoostModel?

请问一下 我在example/conf/rank.conf 中把

rank_predictor {
type: "PredictLinearModel"
using_dict_name: "rank_weights"
}

替换成下面两种
rank_predictor {
type: "PredictXGBoostModel"
using_dict_name: "rank_weights"
}

rank_predictor {
type: "PredictXGBoostModel"
}

但重启后接收请求，发现都会出现以下错误
Require ServerOptions.session_local_data_factory to be set!

请问该如何配置PredictXGBoostModel呢?

Start with example/conf/rank.conf and trace the configuration for PredictXGBoostModel, then search for the Require ServerOptions.session_local_data_factory to be set! error and its session_local_data_factory requirement. Done means a documented working configuration allows requests to complete after restarting the server without this error.

Written by the indexing model from the issue text.