using System;

using System.Threading.Tasks;

​

public class Program

{

    public static async Task SomethingAsync()

    {

        await Task.Delay(5000);

        Console.WriteLine(DateTime.Now + ": task done");

    }

​

    public static void Main(string[] args)

    {

        Console.WriteLine(DateTime.Now + ": hello");

        SomethingAsync().Wait();

        Console.WriteLine(DateTime.Now + ": goodbye");

    }

}