Pushsharp 4 Send FCM notification

  var config = new GcmConfiguration("GOOGLE-API-KEY");
        config.GcmUrl = "https://fcm.googleapis.com/fcm/send";
        // Create a new broker
        var gcmBroker = new GcmServiceBroker(config);

        // Wire up events
        gcmBroker.OnNotificationFailed += (notification, aggregateEx) =>
        {

            aggregateEx.Handle(ex =>
            {

                // See what kind of exception it was to further diagnose
                if (ex is GcmNotificationException)
                {
                    var notificationException = (GcmNotificationException)ex;

                    // Deal with the failed notification
                    var gcmNotification = notificationException.Notification;
                    var description = notificationException.Description;

                    // Console.WriteLine ($"GCM Notification Failed: ID={gcmNotification.MessageId}, Desc={description}");
                }
                else if (ex is GcmMulticastResultException)
                {
                    var multicastException = (GcmMulticastResultException)ex;

                    foreach (var succeededNotification in multicastException.Succeeded)
                    {
                        Console.WriteLine("GCM Notification Failed: ID={succeededNotification.MessageId}");
                    }

                    foreach (var failedKvp in multicastException.Failed)
                    {
                        var n = failedKvp.Key;
                        var e = failedKvp.Value;

                        Console.WriteLine("GCM Notification Failed: ID={n.MessageId}, Desc={e.Description}");
                    }

                }
                else if (ex is DeviceSubscriptionExpiredException)
                {
                    var expiredException = (DeviceSubscriptionExpiredException)ex;

                    var oldId = expiredException.OldSubscriptionId;
                    var newId = expiredException.NewSubscriptionId;

                    Console.WriteLine("Device RegistrationId Expired: {oldId}");

                    //if (!string.IsNullOrWhitespace (newId)) {
                    //    // If this value isn't null, our subscription changed and we should update our database
                    //    Console.WriteLine ("Device RegistrationId Changed To: {newId}");
                    //}
                }
                else if (ex is RetryAfterException)
                {
                    var retryException = (RetryAfterException)ex;
                    // If you get rate limited, you should stop sending messages until after the RetryAfterUtc date
                    Console.WriteLine("GCM Rate Limited, don't send more until after {retryException.RetryAfterUtc}");
                }
                else
                {
                    Console.WriteLine("GCM Notification Failed for some unknown reason");
                }

                // Mark it as handled
                return true;
            });
        };

        gcmBroker.OnNotificationSucceeded += (notification) =>
        {

            Console.WriteLine("GCM Notification Sent!");

        };

        // Start the broker
        gcmBroker.Start();

        foreach (var regId in listofDevices)
        {
            // Queue a notification to send
            gcmBroker.QueueNotification(new GcmNotification
            {
                RegistrationIds = new List<string> {
            regId
        },
                Data = JObject.Parse("{ \"message\" : \"my message\",\"title\" : \"my title\" }"),
                TimeToLive = 500
            });
        }

        // Stop the broker, wait for it to finish
        // This isn't done after every message, but after you're
        // done with the broker
        gcmBroker.Stop();