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:       WASfxr effect = _effects[index];
        effect.enabled = enabled;
        
        // The GainNode is additive so we scale by the total effects active.
        int chans = enabledChannels;
        if (chans > 0)
          _mixer.gain.value = 1.0 - ((chans - 1) / 10.0);
        else
          _mixer.gain.value = 1.0;
        
        trigger();
        return;
  
negative.code: 
    bool init() {
      _mixer = _context.createGain();
      gain = _baseGain;
      
      _mixer.connectNode(_context.destination);
  
  