OrdersController.cs

public class OrdersController : ControllerBase
{
    private readonly ILogger<OrdersController> _logger;
    private readonly IRabbitMQClient _rabbitMqClient;

    public OrdersController(ILogger<OrdersController> logger, IRabbitMQClient rabbitMqClient)
    {
        _logger = logger;
        _rabbitMqClient = rabbitMqClient;
    }
    // ...
    
    [HttpPost]
    public IActionResult Post(NewOrderRequest request)
    {
        var newOrder = new Order
        {
            //...
        };
        Orders.Add(newOrder);
        
        var payload = JsonSerializer.Serialize(newOrder);
        _rabbitMqClient.Publish("ordering", "order.created", payload);

        return CreatedAtAction(nameof(GetById), new { id = newOrder.Id }, newOrder);
    }
}