async init(analyzer) {
        if (!analyzer || typeof analyzer !== "object" || typeof analyzer.init !== "function" || typeof analyzer.parse !== "function") {
            throw new Error("Invalid initialization parameter.");
        }
        else if (this._analyzer == null) {
            await analyzer.init();
            this._analyzer = analyzer;
        }
        else {
            throw new Error("Kuroshiro has already been initialized.");
        }
    }
Initialize Kuroshiro
@memberOf Kuroshiro
@instance
@returns {Promise} Promise object represents the result of initialization