iOS录制现场麦克风数据无法录制和发送?

import UIKit
import AVFoundation

class RecViewController: UIViewController,AVCaptureAudioDataOutputSampleBufferDelegate {

    @IBOutlet weak var recBtn: UIButton!

    let session = AVCaptureSession()
    var result: NSData?

    override func viewDidLoad() {
        super.viewDidLoad()

        self.recBtn.setTitle("RECORDING", for: .normal)
    }

    @IBAction func recBtnAction(_ sender: Any) {

        session.sessionPreset = .medium

        let mic = AVCaptureDevice.default(for: .audio)
        var mic_input: AVCaptureDeviceInput!

        let audio_output = AVCaptureAudioDataOutput()
        audio_output.setSampleBufferDelegate(self, queue: DispatchQueue.main)

        do {
            mic_input = try AVCaptureDeviceInput(device: mic!)
        } catch {
            return
        }

        if session.inputs.isEmpty {
            self.session.addInput(mic_input)
            session.addOutput(audio_output)
        }

        session.startRunning()

    }
    func captureOutput(_ output: AVCaptureOutput, didOutput sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection) {

        let block = CMSampleBufferGetDataBuffer(sampleBuffer)
        var length = 0
        var data: UnsafeMutablePointer<Int8>? = nil

        var status = CMBlockBufferGetDataPointer(block!, 0, nil, &length, &data)    // TODO: check for errors

        result = NSData(bytesNoCopy: data!, length: length, freeWhenDone: false)
    }

    @IBAction func playBtnAction(_ sender: Any) {
        // Storing the ns data and trying to play with following code but it dosent play cant hear a thing
        do {
            let audioPlayer = try AVAudioPlayer(data: result as! Data )
            audioPlayer.prepareToPlay()
            audioPlayer.play()
        } catch {
            print("Error")
        }
    }

}

我用这段代码来记录麦克风的实时数据,但是当我按下rec按钮时什么也没有发生,它既不记录也不去委托和打印,所以如何解决这个问题?(解决)

我已经更新了代码,当我试图通过av音频播放器播放ns数据时,它不会播放任何内容如何解决这个问题?