[SwiftUI] バックグラウンド状態・フォアグラウンド状態の遷移を検知したい

    @Environment(\.scenePhase) private var scenePhase

        .onChange(of: scenePhase) { phase in
            switch phase {
                case .active:
                    print("active")
                case .inactive:
                    print("inactive")
                case .background:
                    print("background")
                @unknown default:
                    print("unknown")
            }
        }

        .onReceive(NotificationCenter.default.publisher(for: UIApplication.didBecomeActiveNotification)) { notification in
            // TODO: 任意の処理
        }