public static long unixTimestamp(long ts) {
    return ts / 1000;
  }
Returns the value of the timestamp to seconds since '1970-01-01 00:00:00' UTC.
amoro-format-mixed/amoro-mixed-flink/amoro-mixed-flink-common/src/main/java/org/apache/amoro/flink/util/DateTimeUtils.java