public class SharedCookieHttpBehavior : IEndpointBehavior
    {
        private static readonly CookieContainer Container = new CookieContainer();
        public void AddBindingParameters(ServiceEndpoint endpoint, BindingParameterCollection bindingParameters)
        {
        }
        public void ApplyClientBehavior(ServiceEndpoint endpoint, ClientRuntime clientRuntime)
        {
            clientRuntime.ClientMessageInspectors.Add(new SharedCookieMessageInspector(Container));
        }
        public void ApplyDispatchBehavior(ServiceEndpoint endpoint, EndpointDispatcher endpointDispatcher)
        {
        }
        public void Validate(ServiceEndpoint endpoint)
        {
        }
        public static string GetCookies(string url)
        {
            string cookie = null;
            if(Container != null)
            {
                var uri = new Uri(url);
                cookie = Container.GetCookieHeader(uri);
            }
            return cookie;
        }
        public static void SetCookieContainer(HttpCookie cookie, Uri uri)
        {
            if (string.IsNullOrWhiteSpace(cookie.Domain))                
                cookie.Domain = uri.Host;
            var header = $"{cookie.Name}={cookie.Value}";
            Container.SetCookies(uri, header);
        }
        public static CookieContainer GetCookieContainer()
        {
            return Container;
        }
    }

 public static class DomainContextExtensions
    {
        public static void ShareCookieContainer(this DomainContext domainContext)
        {
            // Try to get the channel factory property from the domain client 
            // of the domain context. In case that this property does not exist
            // we throw an invalid operation exception.
            var channelFactoryProperty = domainContext.DomainClient.GetType().GetProperty("ChannelFactory");
            if (channelFactoryProperty == null)
            {
                throw new InvalidOperationException("The 'ChannelFactory' property on the DomainClient does not exist.");
            }

            // Now get the channel factory from the domain client and set the
            // new timeout to the binding of the service endpoint.
            var factory = (ChannelFactory)channelFactoryProperty.GetValue(domainContext.DomainClient, null);
            var httpBinding = ((CustomBinding)factory.Endpoint.Binding).Elements.Find<HttpTransportBindingElement>();
            if (httpBinding != null)
            {
                httpBinding.AllowCookies = true;
            }

            var httpsBinding = ((CustomBinding)factory.Endpoint.Binding).Elements.Find<HttpsTransportBindingElement>();
            if (httpsBinding != null)
            {
                httpsBinding.AllowCookies = true;
            }
            factory.Endpoint.EndpointBehaviors.Add(new SharedCookieHttpBehavior());
        }
    }