DemoDelegate.swift

import UIKit
import AVFoundation

class AVFoundataionDemoViewController: BaseViewController {
  var avSpeechSynthesizer: AVSpeechSynthesizer!
  
  override func viewDidLoad() {
    super.viewDidLoad()
    avSpeechSynthesizer = AVSpeechSynthesizer()
    avSpeechSynthesizer.speak(AVSpeechUtterance(string: "Hello world"))
  }
  
  override func viewDidDisappear(_ animated: Bool) {
    super.viewDidDisappear(animated)
    print("viewDidDisappear")
  }
  
  deinit {
    print("AVFoundationDemoViewController is deinit.")
  }
}

extension AVFoundataionDemoViewController: AVSpeechSynthesizerDelegate {
}