Addressing review

Author: alexeyzimarev

src/RestSharp/RestClient.Async.cs

@@ -106,15 +106,16 @@ async Task<HttpResponse> ExecuteRequestAsync(RestRequest request, CancellationTo
             // Make sure we have a cookie container if not provided in the request
             var cookieContainer = request.CookieContainer ??= new CookieContainer();
 
-            if (Options.CookieContainer != null) {
-                cookieContainer.Add(Options.CookieContainer.GetCookies(url));
-            }
-
             var headers = new RequestHeaders()
                 .AddHeaders(request.Parameters)
                 .AddHeaders(DefaultParameters)
                 .AddAcceptHeader(AcceptedContentTypes)
                 .AddCookieHeaders(cookieContainer, url);
+
+            if (Options.CookieContainer != null) {
+                headers.AddCookieHeaders(Options.CookieContainer, url);
+            }
+
             message.AddHeaders(headers);
 
             if (request.OnBeforeRequest != null) await request.OnBeforeRequest(message).ConfigureAwait(false);