getFeatures_() {
    /** @type {import("../Collection.js").default<import("../Feature.js").default>|Array<import("../Feature.js").default>} */
    let features;
    if (this.features_) {
      features = this.features_;
    } else if (this.source_) {
      features = this.source_.getFeatures();
    }
    return features;
  }
@return {import("../Collection.js").default<import("../Feature.js").default>|Array<import("../Feature.js").default>} Features.
@private