Abstract.cs

public abstract class Product(int id, OfferingType type) { }

public class DownloadableProduct(int id, OfferingType type) : Product(id, type)
{
    public Option<string> GetDefaultDownloadFileName()
    {
        return Option.Some("Some Value");
    }

    public Option<string> GetDownloadUrl()
    {
        return Option.Some("Some Value");
    }
}

public sealed class ProductHandler()
{
    public void DoStuff(DownloadableProduct product)
    {
        product.GetDefaultDownloadFileName().MatchSome(
            filename =>
            {
                // Do something with the filename.
            });
        
        product.GetDownloadUrl().MatchSome(
            url =>
            {
                // Do something with the url
            });
    }
}