private static void findSubscriptions(IoTDAClient client)
        {
            ListSubscriptionsRequest req = new ListSubscriptionsRequest
            {
                Marker = "ffffffffffffffffffffffff"
            };

            try
            {
                var resp = client.ListSubscriptions(req);
                Console.WriteLine(resp.HttpStatusCode);
                Console.WriteLine(resp.Count);
                Console.WriteLine(resp.Marker);
                foreach (var Subscription in resp.Subscriptions)
                {
                    Console.WriteLine(JsonConvert.SerializeObject(Subscription));
                }
            }
            catch (RequestTimeoutException requestTimeoutException)
            {
                Console.WriteLine(requestTimeoutException.ErrorMessage);
            }
            catch (ServiceResponseException clientRequestException)
            {
                Console.WriteLine(clientRequestException.HttpStatusCode);
                Console.WriteLine(clientRequestException.ErrorCode);
                Console.WriteLine(clientRequestException.ErrorMsg);
            }
            catch (ConnectionException connectionException)
            {
                Console.WriteLine(connectionException.ErrorMessage);
            }
        }