ConsumerDefinitions.cs

public class OrderSubmittedConsumerDefinition :
    ConsumerDefinition<OrderSubmittedConsumer>
{
    public OrderSubmittedConsumerDefinition()
    {
         EndpointName = "submitted-orders";
         ConcurrentMessageLimit = 4;
    }

    protected override void ConfigureConsumer(IReceiveEndpointConfigurator endpointConfigurator,
        IConsumerConfigurator<OrderSubmittedConsumer> consumerConfigurator)
    {
        endpointConfigurator.UseMessageRetry(r => r.Interval(5, 1000));
        endpointConfigurator.UseInMemoryOutbox();
    }
}

public class PaymentProcessedConsumerDefinition :
    ConsumerDefinition<PaymentProcessedConsumer>
{
    public PaymentProcessedConsumerDefinition()
    {
         EndpointName = "processed-payments";
         ConcurrentMessageLimit = 4;
    }

    protected override void ConfigureConsumer(IReceiveEndpointConfigurator endpointConfigurator,
        IConsumerConfigurator<PaymentProcessedConsumer> consumerConfigurator)
    {
        endpointConfigurator.UseMessageRetry(r => r.Interval(5, 1000));
        endpointConfigurator.UseInMemoryOutbox();
    }
}