SdlDialogFileCallback typedef
        SdlDialogFileCallback =
     Void Function(Pointer<NativeType>  userdata, Pointer<Pointer<Int8> >  filelist, Int32 filter)
    
    
    
Implementation
typedef SdlDialogFileCallback =
    Void Function(
      Pointer<NativeType> userdata,
      Pointer<Pointer<Int8>> filelist,
      Int32 filter,
    );