setWindowProperty function
setWindowProperty changes parameters of a window dynamically.
For further details, please see: https://docs.opencv.org/master/d7/dfc/group__highgui.html#ga66e4a6db4d4e06148bcdfe0d70a5df27
Implementation
void setWindowProperty(String winName, WindowPropertyFlags flag, double value) {
  final cWinName = winName.toNativeUtf8().cast<ffi.Char>();
  cvRun(() => chighgui.cv_setWindowProperty(cWinName, flag.value, value));
  calloc.free(cWinName);
}