如何以编程方式检测iPhone中的耳机？

import AVFoundation

func detectEarbuds() {
    let audioSession = AVAudioSession.sharedInstance()
    do {
        let currentRoute = try audioSession.currentRoute
        let outputs = currentRoute.outputs
        for output in outputs {
            if output.portType == .headphones {
                print("耳机已插入")
            } else {
                print("耳机未插入")
            }
        }
    } catch {
        print("无法检测耳机状态")
    }
}

override func viewDidLoad() {
    super.viewDidLoad()
    NotificationCenter.default.addObserver(self, selector: #selector(routeChanged), name: AVAudioSession.routeChangeNotification, object: nil)
}

@objc func routeChanged(notification: Notification) {
    detectEarbuds()
}