如何录制音频流并保存到文件中/ swift 4.2

import AVFoundation

let audioSession = AVAudioSession.sharedInstance()
do {
    try audioSession.setCategory(.playAndRecord, mode: .default)
    try audioSession.setActive(true)
    audioSession.requestRecordPermission() { allowed in
        if allowed {
            // 录音权限已授权
        } else {
            // 录音权限被拒绝
        }
    }
} catch {
    // 设置音频会话失败
}

let audioFilename = getDocumentsDirectory().appendingPathComponent("recording.wav")

let settings = [
    AVFormatIDKey: Int(kAudioFormatLinearPCM),
    AVSampleRateKey: 44100.0,
    AVNumberOfChannelsKey: 2,
    AVEncoderAudioQualityKey: AVAudioQuality.high.rawValue
]

do {
    audioRecorder = try AVAudioRecorder(url: audioFilename, settings: settings)
    audioRecorder.delegate = self
    audioRecorder.record()
} catch {
    // 创建AVAudioRecorder实例失败
}

func getDocumentsDirectory() -> URL {
    let paths = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
    return paths[0]
}

func audioRecorderDidFinishRecording(_ recorder: AVAudioRecorder, successfully flag: Bool) {
    if flag {
        // 录音完成，可以在此处进行保存文件的操作
    } else {
        // 录音失败
    }
}