CombineNotifications.swift

func observeNotifications(name: NSNotification.Name) -> AnyPublisher<Notification, Never> {
    return Publishers.Deferred<AnyPublisher<Notification, Never>> {
        var observer: NSObjectProtocol?
        return AnyPublisher { subscriber in
            observer = NotificationCenter.default.addObserver(forName: name, object: nil, queue: nil) { notification in
                _ = subscriber.receive(notification)
            }
        }
        .handleEvents(receiveCancel: {
            if let observer = observer {
                NotificationCenter.default.removeObserver(observer)
            }
        })
        .eraseToAnyPublisher()
    }
    .eraseToAnyPublisher()
}

func printNotifications<P: Publisher>(_ notifications: P) where P.Output == Notification, P.Failure == Never {
    notifications.subscribe(AnySubscriber(receiveValue: { (notification: Notification) in
        print(notification)
        return .unlimited
    }))
}