class ViewController: UIViewController {
var iot: MQTTDelegate!

@IBAction func click(_ sender: Any) {
    self.iot = IoT(
                withClientId: "clientId",
                host: "host",
                port: 1883
            )

    iot.connect(username: "username", password: "token")

    iot.publish(topic: "hello", message: "")
}
}