drawKeyPoints function
Implementation
void drawKeyPoints(Mat src, VecKeyPoint keypoints, Mat dst, Scalar color, DrawMatchesFlag flag) {
  cvRun(
    () => cfeatures2d.cv_drawKeyPoints(
      src.ref,
      keypoints.ref,
      dst.ref,
      color.ref,
      flag.value,
      ffi.nullptr,
    ),
  );
}