multiplyAsync function
        
Future<Mat> 
multiplyAsync(
    
- InputArray src1,
- InputArray src2, {
- OutputArray? dst,
- double scale = 1,
- int dtype = -1,
Multiply calculates the per-element scaled product of two arrays. Both input arrays must be of the same size and the same type.
For further details, please see: https://docs.opencv.org/master/d2/de8/group__core__array.html#ga979d898a58d7f61c53003e162e7ad89f
Implementation
Future<Mat> multiplyAsync(
  InputArray src1,
  InputArray src2, {
  OutputArray? dst,
  double scale = 1,
  int dtype = -1,
}) async {
  dst ??= Mat.empty();
  return cvRunAsync0((callback) => ccore.cv_multiply(src1.ref, src2.ref, dst!.ref, scale, dtype, callback), (
    c,
  ) {
    return c.complete(dst);
  });
}