我正在尝试一个简单的例子，在iOS中使用Swift中的AVAudoiRecorder录制音频，我创建了这个类：

import Foundation
import AVFoundation

class AudioRecorder: NSObject, AVAudioRecorderDelegate {
    var audioRecorder: AVAudioRecorder?
    var file: URL? = nil
    
    func setupAudioSession() {
        let session = AVAudioSession.sharedInstance()
        
        do {
            try session.setCategory(.playAndRecord, mode: .default)
            try session.setActive(true)
            try session.overrideOutputAudioPort(.speaker)
            debugPrint("Listo todo")
        } catch {
            print("Error setting up audio session: \(error.localizedDescription)")
        }
    }
    
    func startRecording() {
        file = getDocumentsDirectory().appendingPathComponent("recording.wav")
        
        let settings: [String: Any] = [
            AVFormatIDKey: kAudioFormatLinearPCM,
            AVSampleRateKey: 44100.0,
            AVNumberOfChannelsKey: 2,
            AVLinearPCMBitDepthKey: 16,
            AVLinearPCMIsFloatKey: false,
            AVLinearPCMIsBigEndianKey: false
        ]
        
        do {
            audioRecorder = try AVAudioRecorder(url: file!, settings: settings)
            audioRecorder?.delegate = self
            audioRecorder?.prepareToRecord()
            audioRecorder?.record()
        } catch {
            print("Error starting recording: \(error.localizedDescription)")
        }
    }
    
    func stopRecording() {
        audioRecorder?.stop()
    }
    
    private func getDocumentsDirectory() -> URL {
        let paths = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
        return paths[0]
    }
    
    // MARK: AVAudioRecorderDelegate
    func audioRecorderDidFinishRecording(_ recorder: AVAudioRecorder, successfully flag: Bool) {
        if flag {
            print("Recording was successful.")
        } else {
            print("Recording failed.")
        }
    }
}

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视图调用setupAudioSession，当按下按钮时，我调用startRecording（在此之前，我用AVAudioSession.sharedInstance().requestRecordPermission检查麦克风权限）。
当我按下stop时，我从audioRecorderDidFinishRecording回调的日志中获得一条Recording was successful消息。如果我尝试使用AVAudioPlayer播放文件，我可以正确读取文件属性：

"Playing ... Optional(\"file:///var/mobile/Containers/Data/Application/0760DB3E-440E-4898-83A6-0888EC2EA399/Documents/recording.wav\")"
"Duration: 4.180997732426304"
"Format: <AVAudioFormat 0x281ce80f0:  2 ch,  44100 Hz, Int16, interleaved>"
"Current Time: 0.0"
"Volume: 1.0"

型
但是一点声音都没有。我还在Info.plist中设置了NSMicrophoneUsageDescription来访问麦克风。
我在模拟器和真实的设备中试过，根本没有声音。此外，我已经下载了WAV文件，并在音频编辑器中检查，该文件是空的。
你知道我会错过什么吗看起来像一个真正的例子，所有的东西，我可以找到搜索是非常相似的。