using System;

using System.Threading;

using System.Threading.Tasks;

delegate int SampleDelegate(string data);

public class AsyncExample

{

    public static void Main()

    {

        SampleDelegate counter = new SampleDelegate(CountCharacters);

        SampleDelegate parser = new SampleDelegate(Parse);

        IAsyncResult counterResult = counter.BeginInvoke("hello", null, null);

        IAsyncResult parserResult = parser.BeginInvoke("10", null, null);

        Console.WriteLine("Main thread continuing");

        Console.WriteLine("GetLength returned: {0}", GetLength("Fabulous").GetAwaiter().GetResult());

        Console.WriteLine("Counter returned {0}", counter.EndInvoke(counterResult));

        Console.WriteLine("Parser returned {0}", parser.EndInvoke(parserResult));

        Console.WriteLine("Done");

        Console.ReadLine();

    }

    static async Task<int> GetLength(string text)

    {

        Thread.Sleep(3000);

        return text.Length;

    }

    static int CountCharacters(string text)

    {

        Thread.Sleep(1000);

        Console.WriteLine("Counting characters in {0}", text);

        return text.Length;

    }

    static int Parse(string text)

    {

        Thread.Sleep(100);

        Console.WriteLine("Parsing text {0}", text);

        return int.Parse(text);

    }

}