如何在SwiftUI中使用计时器更新文本

import SwiftUI
import Combine

class TimerManager: ObservableObject {
    @Published var currentTime: String = ""
    private var timer: Timer?
    
    init() {
        timer = Timer.scheduledTimer(withTimeInterval: 1, repeats: true) { _ in
            let formatter = DateFormatter()
            formatter.dateFormat = "HH:mm:ss"
            self.currentTime = formatter.string(from: Date())
        }
    }
}

struct ContentView: View {
    @ObservedObject var timerManager = TimerManager()
    
    var body: some View {
        Text(timerManager.currentTime)
            .font(.largeTitle)
            .padding()
    }
}

func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
    if let windowScene = scene as? UIWindowScene {
        let window = UIWindow(windowScene: windowScene)
        window.rootViewController = UIHostingController(rootView: ContentView())
        self.window = window
        window.makeKeyAndVisible()
    }
}