anchor.diff:    }
   
     void _writeAPP0(_ByteBuffer out) {
  -    out.writeUint16(0xFFE0); // marker
  +    _writeMarker(out, _Jpeg.M_APP0);
       out.writeUint16(16); // length
       out.writeByte(0x4A); // J
       out.writeByte(0x46); // F
  
positive.code:       } else if (t > 255) {
          t = 255;
        }
        YTable[ZigZag[i]] = t;
      }
  
      const List<int> UVQT = const [
  
negative.code:   }
  
    void _writeSOF0(_ByteBuffer out, int width, int height) {
      _writeMarker(out, _Jpeg.M_SOF0);
      out.writeUint16(17);   // length, truecolor YUV JPG
      out.writeByte(8);    // precision
      out.writeUint16(height);
  