AVCaptureAudioDataOutput Is Not Calling AVCaptureAudioDataOutputSampleBufferDelegate.captureOutput

When I run AVCaptureSession with AVCaptureAudioDataOutput, the delegate is not being called. What step am I missing? I appreciate your help!

import Cocoa
import AVFoundation

class ViewController: NSViewController, AVCaptureAudioDataOutputSampleBufferDelegate {
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        let session  = AVCaptureSession()
        
        guard let device = AVCaptureDevice.default(.builtInMicrophone, for: .audio, position: .front) else { return}
        do {
            let input = try AVCaptureDeviceInput(device:device)
            if session.canAddInput(input) {
                session.addInput(input)
                let output = AVCaptureAudioDataOutput()
                output.setSampleBufferDelegate(self, queue: .main)
                if session.canAddOutput(output) {
                    session.addOutput(output)
                }
                
                session.startRunning()
                
                print("Running")
                
            }
        } catch {
        }
    }
    
    func captureOutput(_ output: AVCaptureOutput, didOutput sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection) {
        print(sampleBuffer.numSamples)
    }
}

Did you get any devices? I tried to build your code but didn't get any devices. Anyway, you can look at this answer and also this answer. Also, one thing I can guess, not sure though. Put your capture session variable

let session  = AVCaptureSession()

outside of viewDidLoad.