using System;

using System.Threading.Tasks;       

​

public class Program

{

    static int exported;

    public static void Main()

    {   

            exported=0;

            int[] files = new int[50];

            int tasksCount = 20;

​

            Task[] CSV2JMPTasks = new Task[tasksCount];

​

​

​

            for (int i=0; i< files.Length;)

            {

                for(int j=i; j< tasksCount;j++)

                {

                    if (i < files.Length)

                        CSV2JMPTasks[j] = MyTask(i);

                }

​

​

​

                for (int x=i; x < tasksCount; x++)

                {

                    if (CSV2JMPTasks[x] != null)

                        CSV2JMPTasks[x].Wait();

                }

​

​

                i += tasksCount;

​

            }

    }

    static async Task MyTask(int i)

    {

        await Task.Run(() =>

                       {

                           Console.WriteLine(i);

                           exported+=1;

                       });

​

    }

}