Optional
Called after every row of a page has been yielded. See HistoryPage. It may return a promise: the next page is not requested until it settles, so a checkpoint written here is on disk before anything else happens.
Called after every row of a page has been yielded. See HistoryPage. It may return a promise: the next page is not requested until it settles, so a checkpoint written here is on disk before anything else happens.