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