using System;

using System.Threading.Tasks;

​

public class Program

{

    private static void CallAction(Action actionToInvoke, Action nextActionToInvoke)

    {

        if (actionToInvoke!=null)

        {

            Task.Factory.StartNew(actionToInvoke).ContinueWith( task => nextActionToInvoke.Invoke());

        }

    }

    public static void Main()

    {

        Console.WriteLine("Begin");

        CallAction(()=>Console.WriteLine("actionToInvoke"), ()=>Console.WriteLine("nextActionToInvoke"));

        Console.WriteLine("End");

    }

}