AgoraVideoViewController.swift

var muted = false {
    didSet {
        if muted {
            muteButton.setTitle("Unmute", for: .normal)
        } else {
            muteButton.setTitle("Mute", for: .normal)
        }
    }
}

@IBAction func didToggleMute(_ sender: Any) {
    if muted {
        getAgoraEngine().muteLocalAudioStream(false)
    } else {
        getAgoraEngine().muteLocalAudioStream(true)
    }
    muted = !muted
}