private void RegisterClient(Uri channelUri)
        {
            // Register the URI with 3rd party web service.
            try
            {
                var pushService = new PushServiceClient();
                pushService.RegisterCompleted += (s, e) =>
                {
                    pushService.CloseAsync();

                    Completed(e.Error);
                };

                pushService.RegisterAsync(UserName, channelUri);
            }
            catch (Exception ex)
            {
                Completed(ex);
            }
        }
        private void RegisterClient(Uri channelUri)
        {
            // Register the URI with 3rd party web service.
            try
            {
                var pushService = new PushServiceClient();
                pushService.RegisterCompleted += (s, e) =>
                {
                    pushService.CloseAsync();

                    Completed(e.Error);
                };

                pushService.RegisterAsync(UserName, channelUri);
            }
            catch (Exception ex)
            {
                Completed(ex);
            }
        }