/// <param name='todoItem'>
        /// Required.
        /// </param>
        /// <param name='cancellationToken'>
        /// Cancellation token.
        /// </param>
        public async Task <HttpOperationResponse <TodoItem> > PostTodoItemByTodoitemWithOperationResponseAsync(TodoItem todoItem, CancellationToken cancellationToken = default(System.Threading.CancellationToken))
        {
            // Validate
            if (todoItem == null)
            {
                throw new ArgumentNullException("todoItem");
            }

            // Tracing
            bool   shouldTrace  = ServiceClientTracing.IsEnabled;
            string invocationId = null;

            if (shouldTrace)
            {
                invocationId = ServiceClientTracing.NextInvocationId.ToString();
                Dictionary <string, object> tracingParameters = new Dictionary <string, object>();
                tracingParameters.Add("todoItem", todoItem);
                ServiceClientTracing.Enter(invocationId, this, "PostTodoItemByTodoitemAsync", tracingParameters);
            }

            // Construct URL
            string url = "";

            url = url + "/api/TodoItems";
            string baseUrl = this.Client.BaseUri.AbsoluteUri;

            // Trim '/' character from the end of baseUrl and beginning of url.
            if (baseUrl[baseUrl.Length - 1] == '/')
            {
                baseUrl = baseUrl.Substring(0, baseUrl.Length - 1);
            }
            if (url[0] == '/')
            {
                url = url.Substring(1);
            }
            url = baseUrl + "/" + url;
            url = url.Replace(" ", "%20");

            // Create HTTP transport objects
            HttpRequestMessage httpRequest = new HttpRequestMessage();

            httpRequest.Method     = HttpMethod.Post;
            httpRequest.RequestUri = new Uri(url);

            // Set Headers

            // Set Credentials
            if (this.Client.Credentials != null)
            {
                cancellationToken.ThrowIfCancellationRequested();
                await this.Client.Credentials.ProcessHttpRequestAsync(httpRequest, cancellationToken).ConfigureAwait(false);
            }

            // Serialize Request
            string requestContent = null;
            JToken requestDoc     = todoItem.SerializeJson(null);

            requestContent      = requestDoc.ToString(Newtonsoft.Json.Formatting.Indented);
            httpRequest.Content = new StringContent(requestContent, Encoding.UTF8);
            httpRequest.Content.Headers.ContentType = MediaTypeHeaderValue.Parse("application/json");

            // Send Request
            if (shouldTrace)
            {
                ServiceClientTracing.SendRequest(invocationId, httpRequest);
            }
            cancellationToken.ThrowIfCancellationRequested();
            HttpResponseMessage httpResponse = await this.Client.HttpClient.SendAsync(httpRequest, cancellationToken).ConfigureAwait(false);

            if (shouldTrace)
            {
                ServiceClientTracing.ReceiveResponse(invocationId, httpResponse);
            }
            HttpStatusCode statusCode = httpResponse.StatusCode;

            cancellationToken.ThrowIfCancellationRequested();
            string responseContent = await httpResponse.Content.ReadAsStringAsync().ConfigureAwait(false);

            if (statusCode != HttpStatusCode.OK)
            {
                HttpOperationException <object> ex = new HttpOperationException <object>();
                ex.Request  = httpRequest;
                ex.Response = httpResponse;
                ex.Body     = null;
                if (shouldTrace)
                {
                    ServiceClientTracing.Error(invocationId, ex);
                }
                throw ex;
            }

            // Create Result
            HttpOperationResponse <TodoItem> result = new HttpOperationResponse <TodoItem>();

            result.Request  = httpRequest;
            result.Response = httpResponse;

            // Deserialize Response
            if (statusCode == HttpStatusCode.OK)
            {
                TodoItem resultModel = new TodoItem();
                JToken   responseDoc = null;
                if (string.IsNullOrEmpty(responseContent) == false)
                {
                    responseDoc = JToken.Parse(responseContent);
                }
                if (responseDoc != null)
                {
                    resultModel.DeserializeJson(responseDoc);
                }
                result.Body = resultModel;
            }

            if (shouldTrace)
            {
                ServiceClientTracing.Exit(invocationId, result);
            }
            return(result);
        }