passivelyCollectBFCacheEvents(context) {
    const events = [];
    for (const event of context.dependencies.DevtoolsLog) {
      if (event.method === 'Page.backForwardCacheNotUsed') {
        events.push(event.params);
      }
    }
    return events;
  }
@param {LH.Gatherer.Context<'DevtoolsLog'>} context
@return {LH.Crdp.Page.BackForwardCacheNotUsedEvent[]}