docs: public Interval withDurationBeforeEnd(ReadableDuration duration) {
          long durationMillis = DateTimeUtils.getDurationMillis(duration);
          if (durationMillis == toDurationMillis()) {
              return this;
          }
          Chronology chrono = getChronology();
          long endMillis = getEndMillis();
          long startMillis = chrono.add(endMillis, durationMillis, -1);
          return new Interval(startMillis, endMillis, chrono);
      }