static async Task Main(string[] args)
        {
            DefaultAzureCredential cred   = new DefaultAzureCredential();
            DigitalTwinsClient     client = new DigitalTwinsClient(new Uri("https://mobility-vss.api.wus2.digitaltwins.azure.net"), cred);

            gVehicle = new List <dtdlInterfaceModel>();

            bool loop = true;

            while (loop)
            {
                int    result;
                string c = ReadOptions();

                if (int.TryParse(c, out result))
                {
                    int i = int.Parse(c.ToString());
                    switch (i)
                    {
                    case 0: loop = false;
                        break;

                    case 1: await DigitalTwinMethods.ReadProperty(client);

                        break;

                    case 2: await DigitalTwinMethods.WriteProperty(client);

                        break;

                    case 3: await DigitalTwinModelMethods.ListModels(client);

                        break;

                    case 4: await DigitalTwinModelMethods.GetModel(client);

                        break;

                    case 5: await DigitalTwinModelMethods.GetSchemaType(client);

                        break;

                    case 6: await DigitalTwinModelMethods.CreateModels(client);

                        break;

                    case 7: await DigitalTwinMethods.CreateTwin(client);

                        break;

                    case 8: await DigitalTwinMethods.GetTwin(client);

                        break;

                    case 9: DigitalTwinMethods.DeleteTwin(client);
                        break;

                    case 10: await DigitalTwinMethods.CreateRelationship(client);

                        break;

                    case 11: await DigitalTwinMethods.GetRelationships(client);

                        break;

                    case 12: await DigitalTwinMethods.DeleteRelationship(client);

                        break;

                    default: break;
                    }
                }
            }
        }