closed.cs

class Program
{
    // first argument needs to be a reference type...
    public static int Add(object a, int b) => (int) a + b;

    static void Main(string[] args)
    {
        var a = 1;
        var add1 = (Func<int, int>)Delegate.CreateDelegate(typeof(Func<int, int>), a, typeof(Program).GetMethod("Add"));

        Console.WriteLine(add1(2));
        Console.WriteLine(add1(3));
    }
}