public async Task DeviceMethodTestAsync()
        {
            await this.EnsureServerInitializedAsync();

            int protocolGatewayPort = this.ProtocolGatewayPort;

            string iotHubConnectionString = ConfigurationManager.AppSettings["IotHubClient.ConnectionString"];
            IotHubConnectionStringBuilder hubConnectionStringBuilder = IotHubConnectionStringBuilder.Create(iotHubConnectionString);

            var device = await this.SetupDeviceAsync(iotHubConnectionString);

            await this.CleanupDeviceQueueAsync(hubConnectionStringBuilder.HostName, device);

            var clientScenarios = new ClientScenarios(hubConnectionStringBuilder.HostName, this.deviceId, this.deviceSas);

            var    group      = new MultithreadEventLoopGroup();
            string targetHost = this.tlsCertificate.GetNameInfo(X509NameType.DnsName, false);

            var       readHandler1 = new ReadListeningHandler(CommunicationTimeout);
            Bootstrap bootstrap    = new Bootstrap()
                                     .Group(group)
                                     .Channel <TcpSocketChannel>()
                                     .Option(ChannelOption.TcpNodelay, true)
                                     .Handler(this.ComposeClientChannelInitializer(targetHost, readHandler1));
            IChannel clientChannel = await bootstrap.ConnectAsync(this.ServerAddress, protocolGatewayPort);

            this.ScheduleCleanup(() => clientChannel.CloseAsync());

            // Connect + Subscribe
            await clientScenarios.ConnectAsync(clientChannel, readHandler1).WithTimeout(TestTimeout);

            await clientScenarios.SubscribeAsync(clientChannel, readHandler1).WithTimeout(TestTimeout);

            // Invoke method
            await this.InvokeMethodAsync(iotHubConnectionString, device);

            // Receive and complete
            await this.ReceiveAndCompleteCommandAsync(clientChannel, readHandler1, hubConnectionStringBuilder, device);
        }
        public async Task BasicFunctionalityTest()
        {
            await this.EnsureServerInitializedAsync();

            int protocolGatewayPort = this.ProtocolGatewayPort;

            string iotHubConnectionString = ConfigurationManager.AppSettings["IotHubClient.ConnectionString"];
            IotHubConnectionStringBuilder hubConnectionStringBuilder = IotHubConnectionStringBuilder.Create(iotHubConnectionString);
            bool deviceNameProvided;
            this.deviceId = ConfigurationManager.AppSettings["End2End.DeviceName"];
            if (!string.IsNullOrEmpty(this.deviceId))
            {
                deviceNameProvided = true;
            }
            else
            {
                deviceNameProvided = false;
                this.deviceId = Guid.NewGuid().ToString("N");
            }

            RegistryManager registryManager = RegistryManager.CreateFromConnectionString(iotHubConnectionString);
            if (!deviceNameProvided)
            {
                await registryManager.AddDeviceAsync(new Device(this.deviceId));
                this.ScheduleCleanup(async () =>
                {
                    await registryManager.RemoveDeviceAsync(this.deviceId);
                    await registryManager.CloseAsync();
                });
            }

            Device device = await registryManager.GetDeviceAsync(this.deviceId);
            this.deviceSas =
                new SharedAccessSignatureBuilder
                {
                    Key = device.Authentication.SymmetricKey.PrimaryKey,
                    Target = $"{hubConnectionStringBuilder.HostName}/devices/{this.deviceId}",
                    KeyName = null,
                    TimeToLive = TimeSpan.FromMinutes(20)
                }
                    .ToSignature();

            EventHubClient eventHubClient = EventHubClient.CreateFromConnectionString(iotHubConnectionString, "messages/events");
            EventHubConsumerGroup ehGroup = eventHubClient.GetDefaultConsumerGroup();

            string[] partitionIds = (await eventHubClient.GetRuntimeInformationAsync()).PartitionIds;
            EventHubReceiver[] receivers = await Task.WhenAll(partitionIds.Select(pid => ehGroup.CreateReceiverAsync(pid.Trim(), DateTime.UtcNow)));

            ServiceClient serviceClient = ServiceClient.CreateFromConnectionString(iotHubConnectionString);

            Stopwatch sw = Stopwatch.StartNew();

            await this.CleanupDeviceQueueAsync(hubConnectionStringBuilder.HostName, device);

            var clientScenarios = new ClientScenarios(hubConnectionStringBuilder.HostName, this.deviceId, this.deviceSas);

            var group = new MultithreadEventLoopGroup();
            string targetHost = this.tlsCertificate.GetNameInfo(X509NameType.DnsName, false);

            var readHandler1 = new ReadListeningHandler(CommunicationTimeout);
            Bootstrap bootstrap = new Bootstrap()
                .Group(group)
                .Channel<TcpSocketChannel>()
                .Option(ChannelOption.TcpNodelay, true)
                .Handler(this.ComposeClientChannelInitializer(targetHost, readHandler1));
            IChannel clientChannel = await bootstrap.ConnectAsync(this.ServerAddress, protocolGatewayPort);
            this.ScheduleCleanup(() => clientChannel.CloseAsync());

            Task testWorkTask = Task.Run(async () =>
            {
                Tuple<EventData, string>[] ehMessages = await CollectEventHubMessagesAsync(receivers, 2);
                Tuple<EventData, string> qos0Event = Assert.Single(ehMessages.Where(x => TelemetryQoS0Content.Equals(x.Item2, StringComparison.Ordinal)));
                Tuple<EventData, string> qos1Event = Assert.Single(ehMessages.Where(x => TelemetryQoS1Content.Equals(x.Item2, StringComparison.Ordinal)));

                string qosPropertyName = ConfigurationManager.AppSettings["QoSPropertyName"];

                var qos0Notification = new Message(Encoding.UTF8.GetBytes(NotificationQoS0Content));
                qos0Notification.Properties[qosPropertyName] = "0";
                qos0Notification.Properties["subTopic"] = "tips";
                await serviceClient.SendAsync(this.deviceId, qos0Notification);

                var qos1Notification = new Message(Encoding.UTF8.GetBytes(NotificationQoS1Content));
                qos1Notification.Properties["subTopic"] = "firmware-update";
                await serviceClient.SendAsync(this.deviceId, qos1Notification);

                var qos2Notification = new Message(Encoding.UTF8.GetBytes(NotificationQoS2Content));
                qos2Notification.Properties[qosPropertyName] = "2";
                qos2Notification.Properties["subTopic"] = "critical-alert";
                await serviceClient.SendAsync(this.deviceId, qos2Notification);

                var qos2Notification2 = new Message(Encoding.UTF8.GetBytes(NotificationQoS2Content2));
                qos2Notification2.Properties[qosPropertyName] = "2";
                await serviceClient.SendAsync(this.deviceId, qos2Notification2);
            });

            await clientScenarios.RunPart1StepsAsync(clientChannel, readHandler1).WithTimeout(TestTimeout);
            await testWorkTask.WithTimeout(TestTimeout);

            this.output.WriteLine($"part 1 completed in {sw.Elapsed}");
            await this.EnsureDeviceQueueLengthAsync(hubConnectionStringBuilder.HostName, device, 1);
            this.output.WriteLine($"part 1 clean completed in {sw.Elapsed}");

            string part2Payload = Guid.NewGuid().ToString("N");
            await serviceClient.SendAsync(this.deviceId, new Message(Encoding.ASCII.GetBytes(part2Payload)));

            var readHandler2 = new ReadListeningHandler(CommunicationTimeout);
            IChannel clientChannelPart2 = await bootstrap
                .Handler(this.ComposeClientChannelInitializer(targetHost, readHandler2))
                .ConnectAsync(this.ServerAddress, protocolGatewayPort);
            this.ScheduleCleanup(async () =>
            {
                await clientChannelPart2.CloseAsync();
                await group.ShutdownGracefullyAsync();
            });

            await clientScenarios.RunPart2StepsAsync(clientChannelPart2, readHandler2).WithTimeout(TestTimeout);

            this.output.WriteLine($"Core test completed in {sw.Elapsed}");

            await this.EnsureDeviceQueueLengthAsync(hubConnectionStringBuilder.HostName, device, 0);
        }