code: public LocalTime plusMinutes(long minutesToAdd) {
          if (minutesToAdd == 0) {
              return this;
          }
          int mofd = hour * MINUTES_PER_HOUR + minute;
          int newMofd = ((int) (minutesToAdd % MINUTES_PER_DAY) + mofd + MINUTES_PER_DAY) % MINUTES_PER_DAY;
          if (mofd == newMofd) {
              return this;
          }
          int newHour = newMofd / MINUTES_PER_HOUR;
          int newMinute = newMofd % MINUTES_PER_HOUR;
          return create(newHour, newMinute, second, nano);
      }
docs: Returns a copy of this {@code LocalTime} with the specified number of minutes added.
  <p>
  This adds the specified number of minutes to this time, returning a new time.
  The calculation wraps around midnight.
  <p>
  This instance is immutable and unaffected by this method call.
  
  @param minutesToAdd  the minutes to add, may be negative
  @return a {@code LocalTime} based on this time with the minutes added, not null