anchor.diff:  part of archive;
   
   class InputBuffer {
  -  List<int> buffer;
  +  final List<int> buffer;
     int position = 0;
     final int byteOrder;
   
  
positive.code: 
      return new InputBuffer(buffer.sublist(position, end),
                             byteOrder: byteOrder);
    }
  
    /**
  
negative.code:   /**
     * Return a InputBuffer to read a subset of this buffer.
     * If [position] is not specified, the current read position is
     * used. If [length] is not specified, the remainder of this buffer is used.
     */
    InputBuffer subset([int position, int length]) {
      if (position == null || position < 0) {
  