NServiceBus.Recoverability.RaiseLegacyNotifications C# (CSharp) Method

        static void RaiseLegacyNotifications(FeatureConfigurationContext context)
        {
            var legacyNotifications = context.Settings.Get<Notifications>();
            var notifications = context.Settings.Get<NotificationSubscriptions>();

            notifications.Subscribe<MessageToBeRetried>(e =>
            {
                if (e.IsImmediateRetry)
                {
                    legacyNotifications.Errors.InvokeMessageHasFailedAnImmediateRetryAttempt(e.Attempt, e.Message, e.Exception);
                }
                else
                {
                    legacyNotifications.Errors.InvokeMessageHasBeenSentToDelayedRetries(e.Attempt, e.Message, e.Exception);
                }

                return TaskEx.CompletedTask;
            });

            notifications.Subscribe<MessageFaulted>(e =>
            {
                legacyNotifications.Errors.InvokeMessageHasBeenSentToErrorQueue(e.Message, e.Exception, e.ErrorQueue);
                return TaskEx.CompletedTask;
            });
        }