anchor.diff:        // Remove the value peeked from the buffer list.
         _bufferList.next();
       }
  -    _result.addCharCode(value);
  +    _result.add(value);
       return true;
     }
   }
  
positive.code:   abstract bool _processNext();
  
    _BufferList _bufferList;
    StringBuffer _result;
  }
  
  
  
negative.code:   bool _processNext() {
      while (_bufferList.length > 0) {
        int byte = _bufferList.next();
        _result.add(byte);
      }
      return true;
    }
  