// 'Event' type:
delegate void DelMyEvent();
// consumer:
class Consumer
{
    Producer _theProducer;
    void RegisterForNotification()
    {
       _theProducer.OnMyEvent = new DelMyEvent(OnMyEvent);
    }
    void OnMyEvent() { }
}
// producer:
class Producer
{
   public DelMyEvent OnMyEvent;
   void SendNotification()
   {
      if( OnMyEvent != null ) OnMyEvent();
   }
}

class Program
{
    static void Main(string[] args)
    {
        TestClass.RunTest();
        Console.ReadLine();
    }
}

interface ITestClass
{
    void TestMethod(object sender, TestEventArgs eventErgs);
}

class TestClass : ITestClass
{
    #region Events

    event EventHandler<TestEventArgs> TestEvent;

    #endregion

    #region Constructor

    public TestClass()
    {
        TestEvent += TestMethod;
    }

    #endregion

    #region Public Methods

    public static void RunTest()
    {
        int testCount = 1000000000; //1 000 000 000

        string format = "{0:### ### ### ##0}";

        #region Direct Call

        Console.WriteLine("Direct call");
        TestClass testClass = new TestClass();

        testClass.TestMethod(testClass, new TestEventArgs(3));

        Stopwatch stopwatch = Stopwatch.StartNew();
        for (int i = 0; i < testCount; ++i)
        {
            testClass.TestMethod(testClass, new TestEventArgs(3));
        }
        stopwatch.Stop();
        Console.WriteLine(string.Format(format, stopwatch.ElapsedMilliseconds));
        Console.WriteLine();

        #endregion

        #region Interface Call

        Console.WriteLine("Interface call");
        ITestClass itestClass = new TestClass();
        itestClass.TestMethod(testClass, new TestEventArgs(3));

        stopwatch = Stopwatch.StartNew();
        for (int i = 0; i < testCount; ++i)
        {
            itestClass.TestMethod(testClass, new TestEventArgs(3));
        }
        stopwatch.Stop();
        Console.WriteLine(string.Format(format, stopwatch.ElapsedMilliseconds));
        Console.WriteLine();

        #endregion

        #region Delegate Call

        Console.WriteLine("Delegate call");
        TestClass delegateTestClass = new TestClass();
        Action<object, TestEventArgs> delegateMethod = delegateTestClass.TestMethod;
        delegateMethod(testClass, new TestEventArgs(3));

        stopwatch = Stopwatch.StartNew();
        for (int i = 0; i < testCount; ++i)
        {
            delegateMethod(testClass, new TestEventArgs(3));
        }
        stopwatch.Stop();
        Console.WriteLine(string.Format(format, stopwatch.ElapsedMilliseconds));
        Console.WriteLine();

        #endregion

        #region Event Call

        Console.WriteLine("Event call");
        TestClass eventTestClast = new TestClass();
        eventTestClast.TestEvent(testClass, new TestEventArgs(3));

        stopwatch = Stopwatch.StartNew();
        for (int i = 0; i < testCount; ++i)
        {
            eventTestClast.TestEvent(testClass, new TestEventArgs(3));
        }
        stopwatch.Stop();
        Console.WriteLine(string.Format(format, stopwatch.ElapsedMilliseconds));
        Console.WriteLine();

        #endregion
    }

    #endregion

    #region ITestClass Members

    public void TestMethod(object sender, TestEventArgs e)
    {
        e.Result = e.Value * 3;
    }

    #endregion
}

class TestEventArgs : EventArgs
{
    public int Value { get; private set; }

    public int Result { get; set; }

    public TestEventArgs(int value)
    {
        Value = value;
    }
}