handleDownEvent(mapBrowserEvent) {
    if (this.condition_(mapBrowserEvent)) {
      this.startPixel_ = mapBrowserEvent.pixel;
      this.box_.setMap(mapBrowserEvent.map);
      this.box_.setPixels(this.startPixel_, this.startPixel_);
      this.dispatchEvent(
        new DragBoxEvent(
          DragBoxEventType.BOXSTART,
          mapBrowserEvent.coordinate,
          mapBrowserEvent,
        ),
      );
      return true;
    }
    return false;
  }
Handle pointer down events.
@param {import("../MapBrowserEvent.js").default} mapBrowserEvent Event.
@return {boolean} If the event was consumed.
@override