code: static long lastTimestampInRow(final short metric_width, final KeyValue row) {
      final long base_time = Internal.baseTime(row.key());
      final byte[] qual = row.qualifier();
      return Internal.getTimeStampFromNonDP(base_time, qual);
    }
docs: Package private helper to access the last timestamp in an HBase row.
  
  @param metric_width The number of bytes on which metric IDs are stored.
  @param row A compacted HBase row.
  @return A strictly positive timestamp in seconds or ms.
  @throws IllegalArgumentException if {@code row} doesn't contain any cell.