Trying to get a cookie value which I set on ARCGIS online but not getting any value back?

I am trying to set a cookie in ESRI Arcgis online using ESRI runtime SDK for .net v100.

        var cookie = new CookieHeaderValue("customCookie", cred.Token);             
        var response = Request.CreateResponse(HttpStatusCode.OK, new    {
                                                                            token = cred.Token,
                                                                            expires = cred.ExpirationDate
                                                                        });
        response.Content.Headers.ContentType = new MediaTypeHeaderValue("application/json");            
        response.Headers.AddCookies(new CookieHeaderValue[] { cookie });
        return response;

Now when I try to retrieve that cookie later on in subsequent requests using below I get null.

CookieHeaderValue cookie = context.Request.Headers.GetCookies("customCookie").FirstOrDefault();

I am wondering if there is another way to get the cookie which I set back?

Are you using v100?

If yes, you can try the following code:

        ArcGISHttpClientHandler.HttpRequestBegin += (sender, request) =>
        {
            var cookieContainer = ((System.Net.Http.HttpClientHandler)sender).CookieContainer;
            var cookies = cookieContainer.GetCookies(request.RequestUri);
            var customCookie = new Cookie("customCookie", "someValue") { Domain = request.RequestUri.Host };
            bool foundCookie = false;
            foreach (Cookie cookie in cookies)
            {
                if (cookie.Name == customCookie.Name)
                {
                    foundCookie = true;
                    break;
                }
            }
            if (!foundCookie)
                cookieContainer.Add(customCookie);

        };

ArcGISHttpClientHandler has an event HttpRequestBegin which is invoked on every request. You can use CookieContainer.GetCookies and Add to retrieve/add cookies.