private setStickyHeader(offset: number) {
    let stickyOffset = offset;
    this.scrollStrategy.viewport.elementRef.nativeElement
      .querySelectorAll(stickyHeaderSelector)
      .forEach((el: Element) => {
        const parent = el.parentElement;
        if (!parent) return;
        let baseOffset = 0;
        if (this.stickyPositions?.has(parent)) {
          baseOffset = this.stickyPositions.get(parent)!;
        }
        el.setAttribute('style', `${el.getAttribute('style')} top: ${baseOffset + offset + stickyOffset}px`);
        stickyOffset+= el.getBoundingClientRect().height;
      });
  }