使用Timer.publish时iOS 14的奇怪行为

import Combine
import SwiftUI

class TimerViewModel: ObservableObject {
    @Published var counter: Int = 0
    private var cancellable: AnyCancellable?
    
    func startTimer() {
        cancellable = Timer.publish(every: 1.0, on: .main, in: .default)
            .autoconnect()
            .sink { _ in
                self.counter += 1
            }
    }
    
    func stopTimer() {
        cancellable?.cancel()
    }
}

struct TimerView: View {
    @ObservedObject var timerViewModel = TimerViewModel()
    
    var body: some View {
        VStack {
            Text("Counter: \(timerViewModel.counter)")
                .font(.largeTitle)
                .padding()
            
            Button(action: {
                self.timerViewModel.startTimer()
            }) {
                Text("Start Timer")
                    .padding()
                    .background(Color.blue)
                    .foregroundColor(.white)
                    .cornerRadius(10)
            }
            
            Button(action: {
                self.timerViewModel.stopTimer()
            }) {
                Text("Stop Timer")
                    .padding()
                    .background(Color.red)
                    .foregroundColor(.white)
                    .cornerRadius(10)
            }
        }
    }
}

struct ContentView: View {
    var body: some View {
        TimerView()
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}