public async Task LoadSnapshotWithHttpMessagesAsync()

in ValidateSetup/src/ValidateSetup/MRSServer.cs [4748:4849]
91 lines of code
16 McCabe index (conditional complexity)

        public async Task<HttpOperationResponse> LoadSnapshotWithHttpMessagesAsync(string id, string snapshotId, Dictionary<string, List<string>> customHeaders = null, CancellationToken cancellationToken = default(CancellationToken))
        {
            if (id == null)
            {
                throw new ValidationException(ValidationRules.CannotBeNull, "id");
            }
            if (snapshotId == null)
            {
                throw new ValidationException(ValidationRules.CannotBeNull, "snapshotId");
            }
            // Tracing
            bool _shouldTrace = ServiceClientTracing.IsEnabled;
            string _invocationId = null;
            if (_shouldTrace)
            {
                _invocationId = ServiceClientTracing.NextInvocationId.ToString();
                Dictionary<string, object> tracingParameters = new Dictionary<string, object>();
                tracingParameters.Add("id", id);
                tracingParameters.Add("snapshotId", snapshotId);
                tracingParameters.Add("cancellationToken", cancellationToken);
                ServiceClientTracing.Enter(_invocationId, this, "LoadSnapshot", tracingParameters);
            }
            // Construct URL
            var _baseUrl = BaseUri.AbsoluteUri;
            var _url = new System.Uri(new System.Uri(_baseUrl + (_baseUrl.EndsWith("/") ? "" : "/")), "sessions/{id}/loadsnapshot/{snapshotId}").ToString();
            _url = _url.Replace("{id}", System.Uri.EscapeDataString(id));
            _url = _url.Replace("{snapshotId}", System.Uri.EscapeDataString(snapshotId));
            // Create HTTP transport objects
            var _httpRequest = new HttpRequestMessage();
            HttpResponseMessage _httpResponse = null;
            _httpRequest.Method = new HttpMethod("POST");
            _httpRequest.RequestUri = new System.Uri(_url);
            // Set Headers


            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;
            // Send Request
            if (_shouldTrace)
            {
                ServiceClientTracing.SendRequest(_invocationId, _httpRequest);
            }
            cancellationToken.ThrowIfCancellationRequested();
            _httpResponse = await 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 ErrorException(string.Format("Operation returned an invalid status code '{0}'", _statusCode));
                try
                {
                    _responseContent = await _httpResponse.Content.ReadAsStringAsync().ConfigureAwait(false);
                    Error _errorBody =  SafeJsonConvert.DeserializeObject<Error>(_responseContent, 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 HttpOperationResponse();
            _result.Request = _httpRequest;
            _result.Response = _httpResponse;
            if (_shouldTrace)
            {
                ServiceClientTracing.Exit(_invocationId, _result);
            }
            return _result;
        }