bufr/src/main/java/ucar/nc2/iosp/bufr/BufrIdentificationSection.java
public final CalendarDate getReferenceTime() {
    int sec = (second < 0 || second > 59) ? 0 : second;
    return CalendarDate.of(null, year, month, day, hour, minute, sec);
  }
public final CalendarDate getReferenceTime() {
    int sec = (second < 0 || second > 59) ? 0 : second;
    return CalendarDate.of(null, year, month, day, hour, minute, sec);
  }
return record header time as a CalendarDate

@return referenceTime