anchor.diff:      Map m = {
         "Format": "RSfxr",
         "Name": name,
  +      "Gain": _mixer.gain.value,
         "Channels": chans
       };
       
       return m;
     }
  +  
  +  double toDouble(Object o) {
  +    if (o == null)
  +      return 0.0;
  +    num d = o as num;
  +    return d.toDouble();
  +  }
  +
   }
positive.code:   
    int activeChannel = 0;
    WASfxr effect;
    
    String name = "None";
    
  
negative.code: 
    bool init() {
      _mixer = _context.createGain();
      gain = _baseGain;
      
      _mixer.connectNode(_context.destination);
  
  