using System;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        InitializeWithDefault(out List<Item> items);

        Console.WriteLine($"items == null? {items == null}");

    }

    public static void InitializeWithDefault<T>(out T items)

    {

        Console.WriteLine($"Type: {typeof(T)}");

        items = (T)default;

    }

}

​

public class Item

{

    string Id { get; set; }

}