public abstract class A;
public class A1 : A;

internal class Program
{
    static void Main(string[] args)
    {
        var container = new Container();

        container.Register<object, A1>(serviceKey: "A1");

        var decorateMethod = typeof(Program).SingleMethod(nameof(DecoratorA), true);

        container.Register<object>(made: Made.Of(r => decorateMethod),
                                            setup: Setup.DecoratorOf<A>());

        var res = container.Resolve<object>("A1", args: [ DateTime.Now ]);

        //res is DateTime
    }

    private static object DecoratorA(object t)
    {
        //t is DateTime

        return t;
    }
}