How do I preselect the service that will be chosen in a UIActivityViewController?

Question

I am wondering how Dolly (iOS app) does this. If I select the Twitter icon in the first screenshot, the view in the second screen appears immediately.

That second screenshot is what is presented after you typically click the Twitter service from the scrollable list presented in a UIActivityViewController (below), e.g. Facebook, Mail, Messages, Twitter, etc. But, I never had to click Twitter from the below menu.

Again, the share sheet was presented immediately. I did not have to select Twitter from the built in set of options. So, I am wondering what, if anything I can do to duplicate this behavior. Possibly a few lines that I am missing below?

func handleTwitterShareButtonTapped(){
    let activityVC = UIActivityViewController.init(activityItems: [ShareActivityItemStringSource(), ShareActivityItemURLSource()], applicationActivities: [])

    //preselect twitter from services somehow???

    navigationController?.present(activityVC, animated: true, completion: nil)
}

Or, perhaps there is some swizzling magic that I need to do. If this does involve swizzle magic, any resources that might get me going would be extremely helpful.

Thanks!!!