Present UIActivityViewController from KMM

UIActivityViewController+Show.kt

fun UIActivityViewController.show() {
    val topController = TopMostController ?: return
    if (UIDevice.currentDevice.userInterfaceIdiom == UIUserInterfaceIdiomPad) {
        popoverPresentationController()!!.apply {
            sourceView = topController.presentingViewController!!.view
            sourceRect = CGRectMake(0.0, 0.0, 0.0, 0.0)
        }
    }
    topController.presentViewController(this, true, null)
}

@Suppress("UNCHECKED_CAST")
private val TopMostController: UIViewController?
    get() {
        val window = (UIApplication.sharedApplication.windows as List<UIWindow>).firstOrNull() ?: return null
        var topController = window.rootViewController ?: return null
        while (topController.presentedViewController != null) topController = topController.presentedViewController!!
        return topController
    }