using System;

using System.Collections.Generic;

using System.Runtime.InteropServices;

public class Program

{

    public static void Main()

    {

        var list = new List<string> { "abc", "def", "ghi" };

        ReadOnlySpan<string> subList = CollectionsMarshal.AsSpan(list)[0..1];

        Console.WriteLine(subList.Length);

        Console.WriteLine(subList[0]);

    }

}