public async void ExecuteAddSubscriptionCommand(object parameter)
        {
            Busy        = true;
            BusyContent = "Adding subscription";

            try
            {
                var subscription = new VisSubscriptionObject
                {
                    EndpointURL  = new Uri(Url),
                    IdentityId   = SelectedAcl.IdentityId,
                    IdentityName = SelectedAcl.IdentityName
                };

                await Task.Factory.StartNew(() =>
                {
                    var visService = new VisService();
                    visService.AddSubscription(Id, new List <VisSubscriptionObject>
                    {
                        subscription
                    });
                });

                SubscriptionList.Add(subscription);
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.ToString());
            }
            finally
            {
                Busy = false;
            }
        }