code: private static long getRawTimestamp(long timeMillis) {
          checkArgument(timeMillis >= TIME_MILLIS_MIN, "Time value too small.");  // < 12am Oct 15, 1582 (UTC)
          checkArgument(timeMillis <= TIME_MILLIS_MAX, "Time value too large.");  // > 9:21pm Mar 31, 5236 (UTC)
          return timeMillis * 10000 + NUM_100NS_INTERVALS_SINCE_UUID_EPOCH;
      }
docs: Returns the Date as the number of 100ns intervals since 00:00:00.00,
  15 October 1582 UTC, rounded to a millisecond boundary.