using System;

using System.Diagnostics;               

public class Program

{

    public static void Main()

    {

        var s1 = "a";

        var s2 = "a";

        Stopwatch w1 = new Stopwatch();

        w1.Start();

        Console.WriteLine("s1 == s2: {0}", s1 == s2);

        w1.Stop();

        Console.WriteLine("s1 == s2 time: {0}", w1.Elapsed);

        w1.Reset();

        Console.WriteLine(string.Empty);

        w1.Start();

        Console.WriteLine("string.Equals(s1, s2): {0}", string.Equals(s1, s2));

        w1.Stop();

        Console.WriteLine("string.Equals(s1, s2) time: {0}", w1.Elapsed);

        w1.Reset();

        Console.WriteLine(string.Empty);

        w1.Start();

        Console.WriteLine("string.IsNullOrEmpty(s1) && string.IsNullOrEmpty(s2) && string.Equals(s1, s2): {0}",string.IsNullOrEmpty(s1) && string.IsNullOrEmpty(s2) && string.Equals(s1, s2));

        w1.Stop();

        Console.WriteLine("string.IsNullOrEmpty(s1) && string.IsNullOrEmpty(s2) && string.Equals(s1, s2) time: {0}", w1.Elapsed);

        w1.Reset();

    }

}