nonisolated and isolated in AppDelegate

AppDelegate.swift

fileprivate final class MixenAppDelegate: NSObject, UIApplicationDelegate, MXMetricManagerSubscriber {
    nonisolated let registered = AtomicBool()
    func application(_ application: UIApplication, configurationForConnecting connectingSceneSession: UISceneSession, options: UIScene.ConnectionOptions) -> UISceneConfiguration {
        // Get this out of the critial path of startup, or we will get passed metrics packets to
        // process before the main UI is on-screen
        if OnboardingState.initial.isReadyForUse {
            DispatchQueue.global(qos: .background).asyncAfter(deadline: .now() + 75) {
                self.register()
            }
        }
        
        let configuration = UISceneConfiguration(name: nil, sessionRole: connectingSceneSession.role)
        configuration.delegateClass = MixenSceneDelegate.self
        return configuration
    }
    
    nonisolated func register() {
        if registered.exchange(true) {
            MXMetricManager.shared.add(self)
            Logger.metrics.notice("Registered to collect metrics")
        }
    }
    
    func applicationWillTerminate(_ application: UIApplication) {
        MXMetricManager.shared.remove(self)
    }
    
    nonisolated func didReceive(_ payloads: [MXMetricPayload]) {
        for payload in payloads {
            Logger.misc.debug("Received metrics: \(payload.jsonRepresentation())")
            if let mmx = MixenMetrics2(payload) {
                mmx.send()
            }
        }
    }
}