namespace ConsoleApp1
{
    // 1. Define the delegate with one input and one out parameter
    delegate void SimpleDelegate(string input, out string output);

    // 2. A method that matches the delegate signature
    class Handler
    {
        public static void Process(string input, out string output)
        {
            output = "Processed: " + input;
        }
    }

    // 3. Class that stores and retrieves the delegate
    class DelegateRegistry
    {
        public static readonly Dictionary<string, SimpleDelegate> Registry = new Dictionary<string, SimpleDelegate>();

        public static void Register(string key, SimpleDelegate del)
        {
            Registry[key] = del;
        }
    }
    internal class DelegatePoc
    {
        static void Poc()
        {
            string source = "source";
            SimpleDelegate simpleDelegate = new SimpleDelegate(Handler.Process);
            /// Register the delegate
            DelegateRegistry.Register("key", simpleDelegate);

            // Fetch and call
            if (DelegateRegistry.Registry.TryGetValue("key", out SimpleDelegate del))
            {
                string result;
                del(source, out result);
                Console.WriteLine(result);
            }
        }
    }
}