match method
Calculates the distance between two face features.
faceFeature1	the first input feature
faceFeature2	the second input feature of the same size and the same type as face_feature1
disType	defines how to calculate the distance between two face features
with optional values "FR_COSINE" or "FR_NORM_L2"
Implementation
double match(Mat faceFeature1, Mat faceFeature2, {int disType = FR_COSINE}) {
  final distance = calloc<ffi.Double>();
  cvRun(
    () => cobjdetect.cv_FaceRecognizerSF_match(
      ref,
      faceFeature1.ref,
      faceFeature2.ref,
      disType,
      distance,
      ffi.nullptr,
    ),
  );
  final rval = distance.value;
  calloc.free(distance);
  return rval;
}