watchOS SwiftUI app not founding applicationWillTerminate() function

Question

I am trying to add a function applicationWillTerminate() in my independent watchOS app. With searching from the internet, I found that you can find application life cycle function delegates with using WKExtensionDelegate. But I am unable to find any function or method to detect that app is going to kill. So my main concern is to find a method that will called before independent watchOS app is terminated.

---

import Foundation
import SwiftUI
import WatchKit

final class ExtensionDelegate: NSObject, ObservableObject, WKExtensionDelegate {
    func applicationDidFinishLaunching() {
        NSLog("App launched")
    }
    
    func applicationWillTerminate() {
        NSLog("App will terminate")
      // trying to call this function but is not declared WKExtensionDelegate

    }

    func applicationDidEnterBackground() {
        NSLog("App deactivated")

        NotificationCenter.default.post(name: .appDeactivated, object: nil)
    } 
}