docs: public void setSpanCount(int spanCount) {
          if (spanCount == mSpanCount) {
              return;
          }
          if (spanCount < 1) {
              throw new IllegalArgumentException("Span count should be at least 1. Provided "
                      + spanCount);
          }
          mSpanCount = spanCount;
          mSpanSizeLookup.invalidateSpanIndexCache();
  
          ensureSpanCount();
      }