internal class Program
{
    private static string TopicDevice2Service;
    private static MqttClient client;
    public static void Main(string[] args)
    {

        const string ioTHubName = "myhubname";

        // Azure IoT gateway (MQTT broker)
        const string gatewayHost = "azure-devices.net";
        const int gatewayMqttPort = 8883;

        const string deviceId = "my_device";

        var username = string.Format("{0}/{1}/api-version=2016-11-14", ioTHubName, deviceId);
        var password =
            "SharedAccessSignature sr=myhubname.azure-devices.net&sig=g%2BFmmJxxxxxxE%3D&se=1520101215&skn=iothubowner";

        TopicDevice2Service = string.Format("devices/{0}/messages/events", deviceId);
        try
        {
            client = new MqttClient(gatewayHost, gatewayMqttPort, true, MqttSslProtocols.TLSv1_0, (sender, certificate, chain, errors) => true, null);
            client.Connect(deviceId, username, password);

            while (true)
            {
                client.Publish(TopicDevice2Service, Encoding.UTF8.GetBytes("telemetric_data"));
                System.Threading.Thread.Sleep(2000);
            }
        }
        catch (Exception ex)
        {
            Console.Write(ex.ToString());
        }
    }
}