MixGroupMixCallback typedef
        MixGroupMixCallback =
     Void Function(Pointer<NativeType>  userdata, Pointer<MixGroup>  group, Pointer<SdlAudioSpec>  spec, Pointer<Float>  pcm, Int32 samples)
    
    
    
Implementation
typedef MixGroupMixCallback =
    Void Function(
      Pointer<NativeType> userdata,
      Pointer<MixGroup> group,
      Pointer<SdlAudioSpec> spec,
      Pointer<Float> pcm,
      Int32 samples,
    );