using System;

using System.Collections.Generic;

using System.Threading.Tasks;

public class Program

{

    public static async Task Main()

    {

        test = new string[] { "abc", "def" };

        var t = await Test;

        Console.WriteLine(string.Join("\n", t));

    }

    private static ICollection<string> test;

    public static Task<IEnumerable<string>> Test => Task.FromResult<IEnumerable<string>>(test);

}