Swift AVPlayer 到耳机

我有一个简单的音频播放器，效果很好。我正在播放远程 URL MP3。我的代码:

@IBAction func playAudio(sender: AnyObject) { 
        let url = self.productAudio 
        let playerItem = AVPlayerItem( URL:NSURL( string:url ) ) 
        player = AVPlayer(playerItem:playerItem) 
        player. 
        player.rate = 1.0; 
        player.play() 
} 

但音频是由扬声器输出的。如何通过耳机播放音频？

请您参考如下方法:

swift 5.0

let session = AVAudioSession.sharedInstance() 
 
        do{ 
            try session.setCategory(.playAndRecord) 
            try session.overrideOutputAudioPort(AVAudioSession.PortOverride.none) 
            try session.setActive(true) 
        } catch { 
            print ("\(#file) - \(#function) error: \(error.localizedDescription)") 
        }