blur function
Implementation
VARP blur(VARP src, (int, int) ksize, {int borderType = BORDER_REFLECT}) {
final cKsize = Size.fromTuple(ksize);
final pOut = c.mnn_cv_blur(src.ptr, cKsize.ref, borderType);
final rval = VARP.fromPointer(pOut);
cKsize.dispose();
return rval;
}