Dependencies and the delegate pattern

[pieterjongsma]

I am curious what would be the recommended way to implement a delegate pattern for a dependency. I couldn't find the pattern in any of the library provided dependencies and the right choice does not seem obvious to me.

I'm dealing with WCSession/WCSessionDelegate in my code. I've created a WatchConnectivityManager struct as a DependencyKey with functions such as var transferFile: @Sendable (_ url: URL, _ metadata: FileTransferMetadata?) -> Void.

I would also like to be notified when file transfers arrive and so I've created a WatchConnecitivityDelegate class for that, implementing func session(_ session: WCSession, didReceive file: WCSessionFile). When constructing the liveValue, I instantiate and assign the delegate to the WCSession.

How do I now bubble up the messages to, for example, a database?

Some options I've considered:

1. Implement a onFileReceived function on the WatchConnectivityManager dependency to be overridden (not possible, because the dependency is a struct/read only?)
2. Use a (non @dependency) singleton as the delegate (seems like an anti pattern)
3. Don't bubble up, but make the database a dependency of WatchConnectivityDelegate

None of those seem great to me. I would really appreciate some hints on how to best implement this.

I'm not using Composable Architecture but am attempting to implement according to the Modern SwiftUI episodes on pointfree.co