Is using the "calshow" openURL scheme allowed in situations where it's useful?
It's not in the Apple URL Scheme Reference but that might just be outdated.
Since it's just a URL I wouldn't see it as an API, thus not as a private API either.
But still, it'd be nice to get a clear statement on that.
Code would look like this:
UIApplication.shared.openURL(URL(string: "calshow:\(event.startDate.timeIntervalSinceReferenceDate)")!)