sub _is_unicode {
  if ($] >= 5.8) {
    eval(q`
      if ( $data =~ /[\x{100}-\x{10FFFF}]/s) { return 1 ;}}
    `);
  }
  else {
    ## No Perl support for UTF-8! ;-/
    return undef ;
  }

  return undef ;
}