using System;

using System.Threading;

using System.Threading.Tasks;

public class Program

{

public void Main()

{

    var test = new GwPInvokes();

    var tcs = new TaskCompletionSource<Tuple<string, string>>();

    test.find_gw(null, 0, new GwPInvokes.Callback(new Action<IntPtr, string, string>((ptr, gwddr, gwname) => tcs.SetResult(new Tuple<string,string>(gwddr, gwname)))));

    var result =  tcs.Task.Result;

    Console.WriteLine("Job is done: {0}, {1}", result.Item1, result.Item2);

}

​

​

​

class GwPInvokes

{

    public delegate void Callback(IntPtr ptr,string gwddr,string gwname);

    public bool find_gw(object broadcastaddr, int timeout, Callback callback)

    {

        Task.Run(() =>

        {

            Thread.Sleep(1500);

            callback(IntPtr.Zero, "aaa", "bbb");

        });

        return false;

    }

}

}