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我试图在应用程序进入后台时锁定我的应用程序，当应用程序在前台时，用户可以使用生物识别（FaceID/TouchID）身份验证解锁应用程序。

这是我的代码的一个简单、可重现的示例：

import LocalAuthentication
import SwiftUI

struct ContentView: View {
    @State var isUnlocked = false
    
    var body: some View {
        if isUnlocked { 

            // if the app is unlocked, app shows the text "Unlocked"
            Text("Unlocked")
                .font(.title)

                // app gets locked when the app goes to background
                .onReceive(NotificationCenter.default.publisher(for: UIApplication.willResignActiveNotification)) { _ in
                    self.isUnlocked = false
                    print("locked the app")
                }

        } else { 

            // if the app is locked, app shows the text "Locked" and app should show prompt FaceID/TouchID prompt
            Text("LOCKED")
                .font(.title)

                // FaceID prompt shows when the app opens (from Non-running state)
                .onAppear(perform: authenticate)

                // FaceID prompt shows when the app coming from background to foreground
                .onReceive(NotificationCenter.default.publisher(for: UIApplication.willEnterForegroundNotification)) { _ in
                    authenticate()
                    print("back inside the app")
                }
        }
        
    }
    
    // I use this to prompt the biometric authentication
    func authenticate() {
        let context = LAContext()
        var error: NSError?
        
        if context.canEvaluatePolicy(.deviceOwnerAuthenticationWithBiometrics, error: &error) {
            let reason = "We need to unlock your data"
            
            context.evaluatePolicy(.deviceOwnerAuthenticationWithBiometrics, localizedReason: reason) { success, authenticationError in
                DispatchQueue.main.async {
                    if success {
                        // app gets unlocked if biometrix authentication succeeded
                        self.isUnlocked = true
                    } else {
                        // authentication failed
                    }
                }
            }
        } else {
            // no biometrics
        }
    }

}

当用户打开应用程序（从非运行状态）时，FaceID 提示会立即显示，不会有任何延迟。但是当应用程序从后台转到前台时，FaceID 提示大约需要 5 秒才能显示出来。当应用程序从后台转到前台时，我使用相同的功能authenticate()来提示生物识别身份验证和 Xcode 控制台打印。那么导致 FaceID 延迟的原因是什么？"back inside the app"

请帮我。谢谢。

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