async _start() {
    if (__privateGet(this, _startDone) === true)
      return;
    await this.doRoute(this.keepHashFromUrl(window.location.hash));
    window.addEventListener("hashchange", (event) => this._hashChange(event));
    document.dispatchEvent(new CustomEvent("uibrouter:loaded"));
    if (this.uibuilder)
      uibuilder.set("uibrouter", "loaded");
    __privateSet(this, _startDone, true);
  }
Called once all external templates have been loaded