Browse Questions
  • All three are test doubles — fake objects used in place of real dependencies — but with different roles.
  • AsyncStream converts callback or delegate-based event sources into an AsyncSequence you can iterate over with for await.
  • Generate the pair with TSKeyGen, then persist only the private key in the Keychain with a restrictive accessibility class and hand the public key to the server during enrolment.
  • Both static and class define type-level properties and methods, but static members cannot be overridden by subclasses (final), whereas class members allow dynamic dispatch and can be overridden.

Answer: AsyncStream converts callback or delegate-based event sources into an AsyncSequence you can iterate over with for await. It bridges event-driven code into structured concurrency.

Code Example:

// Wrapping a delegate/callback pattern into AsyncStream
func locationUpdates() -> AsyncStream<CLLocation> {
    AsyncStream { continuation in
        let manager = CLLocationManager()
        let delegate = LocationDelegate { location in
            continuation.yield(location)     // emit each update
        }
        manager.delegate = delegate
        manager.startUpdatingLocation()

        continuation.onTermination = { _ in
            manager.stopUpdatingLocation()   // cleanup on cancel
        }
    }
}

// Consuming it cleanly with for await
Task {
    for await location in locationUpdates() {
        print("New location: \(location.coordinate)")
    }
}

Use for: Location updates, WebSocket messages, notifications, sensor data, any ongoing event stream.