anchor.diff:    }
   }
   
  -bool isWhitespace(String text, int index) {
  -  final int rune = text.codeUnitAt(index);
  +/// Returns true if the code unit at [index] in [text] is a whitespace
  +/// character.
  +///
  +/// Based on: https://en.wikipedia.org/wiki/Whitespace_character#Unicode
  +bool _isWhitespace(String text, int index) {
  +  var rune = text.codeUnitAt(index);
     return rune >= 0x0009 && rune <= 0x000D ||
         rune == 0x0020 ||
         rune == 0x0085 ||
  
positive.code:         result.add(text.substring(currentLineStart, i));
  
          // Skip any intervening whitespace.
          while (isWhitespace(text, i) && i < text.length) i++;
  
          currentLineStart = i;
          lastWhitespace = null;
  
negative.code:     var currentLineStart = 0;
      int lastWhitespace;
      for (var i = 0; i < text.length; ++i) {
        if (_isWhitespace(text, i)) lastWhitespace = i;
  
        if (i - currentLineStart >= length) {
          // Back up to the last whitespace, unless there wasn't any, in which
  