using System;

​

public class Process

{

    public delegate void Callback(int msg);

    // work that takes cpu time

    void Run(int id)

    {

        Console.WriteLine("Running process {0}....", id);

    }

​

    public void Start(int id, Callback callback)

    {

        Run(id);

        // when work is done, invoke the callback

        callback(id);

    }

​

    public void Log(int id)

    {

        Console.WriteLine("Instance:Complete process {0}", id);

    }

}

​

public class Program

{

    public static void Main()

    {

        Process process = new Process();

        process.Start(1, process.Log);

        process.Start(12, Log);

    }

​

    public static void Log(int id)

    {

        Console.WriteLine("Static:Complete process {0}", id);

    }

}