code: public void complete (ValidationResult validationResult) {
          if (!allTravelTimesAreRounded) storeErrors(travelTimeZeroErrors);
          else registerError(NewGTFSError.forFeed(FEED_TRAVEL_TIMES_ROUNDED, null));
      }
docs: Completing this feed validator means checking if there were any unrounded travel times in the feed and (if so)
  registering any zero travel time errors that were passed over before the first unrounded travel time was
  encountered. If in fact all travel times are rounded to the minute, store a special feed-wide error in this case.