using System;

using System.Collections.Generic;

using System.Threading.Tasks;

​

public class Program

{

    public static void Main()

    {

        Task.WaitAll(EmailService());

    }

    public static async Task EmailService()

    {

        // Write a service function that sends 100 emails and awaits their completion.

        // The service is limited to sending 10 emails at a time.

    }

    public static async Task SendEmail(int batchNumber, int emailNumberInBatch, int emailNumberTotal) {

        await Task.Delay(10);

        Console.WriteLine(string.Format("Email sent -- Batch = {0}, Email in batch = {1}, Email total = {2}", batchNumber, emailNumberInBatch, emailNumberTotal));

    }

}