private Exception ParseResponse(GraphErrorException graphEx)
        {
            int exceptionMessageIndex = graphEx.Response.Content.IndexOf("\"value\":", StringComparison.CurrentCultureIgnoreCase);

            if (exceptionMessageIndex > 0)
            {
                string substring = graphEx.Response.Content.Substring(exceptionMessageIndex + 9);
                // the start index is added 9, so as to remove the delimiter \"value\":\
                string exceptionDetails = substring.Substring(0, substring.IndexOf("\"}"));
                return(new Exception(exceptionDetails));
            }
            return(null);
        }
        /// <summary>
        /// Gets the details for the currently logged-in user.
        /// </summary>
        /// <param name='customHeaders'>
        /// Headers that will be added to request.
        /// </param>
        /// <param name='cancellationToken'>
        /// The cancellation token.
        /// </param>
        /// <exception cref="GraphErrorException">
        /// Thrown when the operation returned an invalid status code
        /// </exception>
        /// <exception cref="SerializationException">
        /// Thrown when unable to deserialize the response
        /// </exception>
        /// <exception cref="ValidationException">
        /// Thrown when a required parameter is null
        /// </exception>
        /// <exception cref="System.ArgumentNullException">
        /// Thrown when a required parameter is null
        /// </exception>
        /// <return>
        /// A response object containing the response body and response headers.
        /// </return>
        public async Task <AzureOperationResponse <User> > GetWithHttpMessagesAsync(Dictionary <string, List <string> > customHeaders = null, CancellationToken cancellationToken = default(CancellationToken))
        {
            if (Client.ApiVersion == null)
            {
                throw new ValidationException(ValidationRules.CannotBeNull, "this.Client.ApiVersion");
            }
            if (Client.TenantID == null)
            {
                throw new ValidationException(ValidationRules.CannotBeNull, "this.Client.TenantID");
            }
            // Tracing
            bool   _shouldTrace  = ServiceClientTracing.IsEnabled;
            string _invocationId = null;

            if (_shouldTrace)
            {
                _invocationId = ServiceClientTracing.NextInvocationId.ToString();
                Dictionary <string, object> tracingParameters = new Dictionary <string, object>();
                tracingParameters.Add("cancellationToken", cancellationToken);
                ServiceClientTracing.Enter(_invocationId, this, "Get", tracingParameters);
            }
            // Construct URL
            var _baseUrl = Client.BaseUri.AbsoluteUri;
            var _url     = new System.Uri(new System.Uri(_baseUrl + (_baseUrl.EndsWith("/") ? "" : "/")), "{tenantID}/me").ToString();

            _url = _url.Replace("{tenantID}", System.Uri.EscapeDataString(Client.TenantID));
            List <string> _queryParameters = new List <string>();

            if (Client.ApiVersion != null)
            {
                _queryParameters.Add(string.Format("api-version={0}", System.Uri.EscapeDataString(Client.ApiVersion)));
            }
            if (_queryParameters.Count > 0)
            {
                _url += (_url.Contains("?") ? "&" : "?") + string.Join("&", _queryParameters);
            }
            // Create HTTP transport objects
            var _httpRequest = new HttpRequestMessage();
            HttpResponseMessage _httpResponse = null;

            _httpRequest.Method     = new HttpMethod("GET");
            _httpRequest.RequestUri = new System.Uri(_url);
            // Set Headers
            if (Client.GenerateClientRequestId != null && Client.GenerateClientRequestId.Value)
            {
                _httpRequest.Headers.TryAddWithoutValidation("x-ms-client-request-id", System.Guid.NewGuid().ToString());
            }
            if (Client.AcceptLanguage != null)
            {
                if (_httpRequest.Headers.Contains("accept-language"))
                {
                    _httpRequest.Headers.Remove("accept-language");
                }
                _httpRequest.Headers.TryAddWithoutValidation("accept-language", Client.AcceptLanguage);
            }


            if (customHeaders != null)
            {
                foreach (var _header in customHeaders)
                {
                    if (_httpRequest.Headers.Contains(_header.Key))
                    {
                        _httpRequest.Headers.Remove(_header.Key);
                    }
                    _httpRequest.Headers.TryAddWithoutValidation(_header.Key, _header.Value);
                }
            }

            // Serialize Request
            string _requestContent = null;

            // Set Credentials
            if (Client.Credentials != null)
            {
                cancellationToken.ThrowIfCancellationRequested();
                await Client.Credentials.ProcessHttpRequestAsync(_httpRequest, cancellationToken).ConfigureAwait(false);
            }
            // Send Request
            if (_shouldTrace)
            {
                ServiceClientTracing.SendRequest(_invocationId, _httpRequest);
            }
            cancellationToken.ThrowIfCancellationRequested();
            _httpResponse = await Client.HttpClient.SendAsync(_httpRequest, cancellationToken).ConfigureAwait(false);

            if (_shouldTrace)
            {
                ServiceClientTracing.ReceiveResponse(_invocationId, _httpResponse);
            }
            HttpStatusCode _statusCode = _httpResponse.StatusCode;

            cancellationToken.ThrowIfCancellationRequested();
            string _responseContent = null;

            if ((int)_statusCode != 200)
            {
                var ex = new GraphErrorException(string.Format("Operation returned an invalid status code '{0}'", _statusCode));
                try
                {
                    _responseContent = await _httpResponse.Content.ReadAsStringAsync().ConfigureAwait(false);

                    GraphError _errorBody = Rest.Serialization.SafeJsonConvert.DeserializeObject <GraphError>(_responseContent, Client.DeserializationSettings);
                    if (_errorBody != null)
                    {
                        ex.Body = _errorBody;
                    }
                }
                catch (JsonException)
                {
                    // Ignore the exception
                }
                ex.Request  = new HttpRequestMessageWrapper(_httpRequest, _requestContent);
                ex.Response = new HttpResponseMessageWrapper(_httpResponse, _responseContent);
                if (_shouldTrace)
                {
                    ServiceClientTracing.Error(_invocationId, ex);
                }
                _httpRequest.Dispose();
                if (_httpResponse != null)
                {
                    _httpResponse.Dispose();
                }
                throw ex;
            }
            // Create Result
            var _result = new AzureOperationResponse <User>();

            _result.Request  = _httpRequest;
            _result.Response = _httpResponse;
            if (_httpResponse.Headers.Contains("x-ms-request-id"))
            {
                _result.RequestId = _httpResponse.Headers.GetValues("x-ms-request-id").FirstOrDefault();
            }
            // Deserialize Response
            if ((int)_statusCode == 200)
            {
                _responseContent = await _httpResponse.Content.ReadAsStringAsync().ConfigureAwait(false);

                try
                {
                    _result.Body = Rest.Serialization.SafeJsonConvert.DeserializeObject <User>(_responseContent, Client.DeserializationSettings);
                }
                catch (JsonException ex)
                {
                    _httpRequest.Dispose();
                    if (_httpResponse != null)
                    {
                        _httpResponse.Dispose();
                    }
                    throw new SerializationException("Unable to deserialize the response.", _responseContent, ex);
                }
            }
            if (_shouldTrace)
            {
                ServiceClientTracing.Exit(_invocationId, _result);
            }
            return(_result);
        }