using System;

using System.Threading;

​

public static class Extensions

{

    public static DateTime TrimMilliseconds(this DateTime dt)

    {

        return new DateTime(dt.Year, dt.Month, dt.Day, dt.Hour, dt.Minute, dt.Second, 0, dt.Kind);

    }

}

​

public class Program

{

    public static void Main()

    {

        var start = DateTime.Now.TrimMilliseconds().TimeOfDay;

        Thread.Sleep(50);

        var now = DateTime.Now.TrimMilliseconds().TimeOfDay;

        if (now == start)

        {

            Console.WriteLine("Fount at " + now + " " + start);

        }

        else

            Console.WriteLine("arg");

    }

}