C#: How do you implement events?

1public class OrderService
2{
3    public event EventHandler<OrderEventArgs> OrderCreated;
4
5    public void CreateOrder(Order order)
6    {
7        // Create order...
8        OrderCreated?.Invoke(this, new OrderEventArgs(order));
9    }
10}

1var service = new OrderService();
2service.OrderCreated += OnOrderCreated;
3
4void OnOrderCreated(object sender, OrderEventArgs e)
5{
6    Console.WriteLine($"Order {e.Order.Id} created");
7}