code: @Override  // override for Javadoc and performance
      public int compareTo(ChronoLocalDateTime<?> other) {
          if (other instanceof LocalDateTime) {
              return compareTo0((LocalDateTime) other);
          }
          return super.compareTo(other);
      }
docs: Compares this date-time to another date-time.
  <p>
  The comparison is primarily based on the date-time, from earliest to latest.
  It is "consistent with equals", as defined by {@link Comparable}.
  <p>
  If all the date-times being compared are instances of {@code LocalDateTime},
  then the comparison will be entirely based on the date-time.
  If some dates being compared are in different chronologies, then the
  chronology is also considered, see {@link ChronoLocalDateTime#compareTo}.
  
  @param other  the other date-time to compare to, not null
  @return the comparator value, negative if less, positive if greater