_cacheWidths() {
      const map = this._breadcrumbItemWidths,
        items = this._getItems(),
        label = this._currentLocationLabel;
      for (let i = this._overflowSize; i < items.length; i++) {
        const item = items[i],
          link = this.shadowRoot.querySelector(`#${item._id}-link-wrapper`);
        map.set(item, this._getElementWidth(link));
      }
      if (items.length && this._endsWithCurrentLocationLabel && label) {
        const item = items[items.length - 1];
        map.set(item, this._getElementWidth(label));
      }
      if (!this._isOverflowEmpty) {
        const arrow = this.shadowRoot.querySelector(".ui5-breadcrumbs-dropdown-arrow-link-wrapper");
        this._dropdownArrowLinkWidth = this._getElementWidth(arrow);
      }
    }
Caches the space required to render the content
@private