Policy.cs

public class PlaceOrderHandler : RequestHandler<PlaceOrder>
{
    private readonly IAmACommandProcessor _commandProcessor;

    public PlaceOrderHandler(IAmACommandProcessor commandProcessor)
    {
        _commandProcessor = commandProcessor;
    }

    [UsePolicy(CommandProcessor.RETRYPOLICY, 3)]
    public override PlaceOrder Handle(PlaceOrder command)
    {
        throw new InvalidOperationException();

        return base.Handle(command);
    }
}