code: public static int compareQualifiers(final byte[] a, final int offset_a, 
        final byte[] b, final int offset_b) {
      final long left = Internal.getOffsetFromQualifier(a, offset_a);
      final long right = Internal.getOffsetFromQualifier(b, offset_b);
      if (left == right) {
        return 0;
      }
      return (left < right) ? -1 : 1;
    }
docs: Compares two data point byte arrays with offsets.
  Can be used on:
  <ul><li>Single data point columns</li>
  <li>Compacted columns</li></ul>
  <b>Warning:</b> Does not work on Annotation or other columns
  @param a The first byte array to compare
  @param offset_a An offset for a
  @param b The second byte array
  @param offset_b An offset for b
  @return 0 if they have the same timestamp, -1 if a is less than b, 1
  otherwise.
  @since 2.0