 (const event of mainThread.sliceGroup.childEvents()) {
      if (!rangeOfInterest.intersectsRangeExclusive(event.range)) continue;
      const eventSelfTime = getEventSelfTime(event, rangeOfInterest);
      const title =
          tr.e.chrome.ChromeUserFriendlyCategoryDriver.fromEvent(event);

      breakdownTree[title].total += eventSelfTime;
      if (breakdownTree[title].events[event.title] === undefined) {
        breakdownTree[title].events[event.title] = 0;
      }
      breakdownTree[title].events[e