forwardAsync method
Implementation
Future<Mat> forwardAsync({String outputName = ""}) async {
final rval = cvRunAsync<Mat>(
(callback) => cffi.Net_Forward_Async(ref, outputName.toNativeUtf8().cast<ffi.Char>(), callback),
(c, result) => c.complete(Mat.fromPointer(result.cast<cvg.Mat>())),
);
return rval;
}