@Override
  protected long getDateField(long days) {
    date.setTimeInDays((int) days);
    return TimestampTZUtil.convert(date, timeZone).getEpochSecond();
  }
Return Unix Timestamp.
Extends {@link VectorUDFTimestampFieldDate}
ql/src/java/org/apache/hadoop/hive/ql/exec/vector/expressions/VectorUDFUnixTimeStampDate.java