cornerSubPixAsync function
        
Future<VecPoint2f> 
cornerSubPixAsync(
    
- InputArray image,
- VecPoint2f corners,
- (int, int) winSize,
- (int, int) zeroZone, [
- (int, int, double) criteria = (TERM_COUNT + TERM_EPS, 30, 1e-4),
CornerSubPix Refines the corner locations. The function iterates to find the sub-pixel accurate location of corners or radial saddle points.
For further details, please see: https:///docs.opencv.org/master/dd/d1a/group__imgproc__feature.html#ga354e0d7c86d0d9da75de9b9701a9a87e
Implementation
Future<VecPoint2f> cornerSubPixAsync(
  InputArray image,
  VecPoint2f corners,
  (int, int) winSize,
  (int, int) zeroZone, [
  (int, int, double) criteria = (TERM_COUNT + TERM_EPS, 30, 1e-4),
]) {
  final size = winSize.cvd;
  final zone = zeroZone.cvd;
  final c = criteria.toTermCriteria();
  return cvRunAsync0(
    (callback) => cimgproc.cv_cornerSubPix(image.ref, corners.ref, size.ref, zone.ref, c.ref, callback),
    (c) {
      return c.complete(corners);
    },
  );
}