docs: public Timespan substractWithZeroFloor(Timespan other) {
          if (getTimeUnit() == other.getTimeUnit()) {
              long delta = Math.max(0, getDuration() - other.getDuration());
              return new Timespan(delta, getTimeUnit());
          }
  
          long delta = Math.max(0, getDurationInMilliseconds() - other.getDurationInMilliseconds());
  
          return new Timespan(delta, TimeUnit.MILLISECOND);
      }