code: public boolean isAfter(ChronoZonedDateTime<?> other) {
          long thisEpochSec = toEpochSecond();
          long otherEpochSec = other.toEpochSecond();
          return thisEpochSec > otherEpochSec ||
              (thisEpochSec == otherEpochSec && toLocalTime().getNano() > other.toLocalTime().getNano());
      }
docs: Checks if the instant of this date-time is after that of the specified date-time.
  <p>
  This method differs from the comparison in {@link #compareTo} in that it
  only compares the instant of the date-time. This is equivalent to using
  {@code dateTime1.toInstant().isAfter(dateTime2.toInstant());}.
  
  @param other  the other date-time to compare to, not null
  @return true if this is after the specified date-time