static makeSubItems(entity, summaries) {
    const entityURLs = summaries.urls.get(entity) || [];
    const items = entityURLs
      .map(url => /** @type {URLSummary} */ ({url, ...summaries.byURL.get(url)}))
      // Sort by blocking time first, then transfer size to break ties.
      .sort((a, b) => (b.blockingTime - a.blockingTime) || (b.transferSize - a.transferSize));

    return items;
  }
@param {LH.Artifacts.Entity} entity
@param {SummaryMaps} summaries
@return {Array<URLSummary>}