NServiceBus.DelayedRetryExecutor.Retry C# (CSharp) Method

        public async Task<int> Retry(IncomingMessage message, TimeSpan delay, TransportTransaction transportTransaction)
        {
            var outgoingMessage = new OutgoingMessage(message.MessageId, new Dictionary<string, string>(message.Headers), message.Body);

            var currentDelayedRetriesAttempt = message.GetDelayedDeliveriesPerformed() + 1;

            outgoingMessage.SetCurrentDelayedDeliveries(currentDelayedRetriesAttempt);
            outgoingMessage.SetDelayedDeliveryTimestamp(DateTime.UtcNow);

            UnicastAddressTag messageDestination;
            List<DeliveryConstraint> deliveryConstraints = null;
            if (timeoutManagerAddress == null)
            {
                // transport supports native deferred messages, directly send to input queue with delay constraint:
                deliveryConstraints = new List<DeliveryConstraint>(1)
                {
                    new DelayDeliveryWith(delay)
                };
                messageDestination = new UnicastAddressTag(endpointInputQueue);
            }
            else
            {
                // transport doesn't support native deferred messages, reroute to timeout manager:
                outgoingMessage.Headers[TimeoutManagerHeaders.RouteExpiredTimeoutTo] = endpointInputQueue;
                outgoingMessage.Headers[TimeoutManagerHeaders.Expire] = DateTimeExtensions.ToWireFormattedString(DateTime.UtcNow + delay);
                messageDestination = new UnicastAddressTag(timeoutManagerAddress);
            }

            var transportOperations = new TransportOperations(new TransportOperation(outgoingMessage, messageDestination, deliveryConstraints: deliveryConstraints));

            await dispatcher.Dispatch(transportOperations, transportTransaction, new ContextBag()).ConfigureAwait(false);

            return currentDelayedRetriesAttempt;
        }