using System;

using System.Collections.Generic;

using System.Linq;

using System.Threading;

using System.Threading.Tasks;

public class Program

{

    private static Task WriteAsync(string filename)

    {

        return Task.Run(() => {

            Console.WriteLine("File {0} start writing!", filename);

            Thread.Sleep(1000);

            Console.WriteLine("File {0} finish writing!", filename);

        });

    }

    private static async Task CopyDocToDirectory(string filename)

    {

        await WriteAsync(filename);

    }

    private static void ProcessDocsAndCopyToDirectory(List<string> docsList)

    {

        Task.WhenAll(docsList.Select(doc =>

            Task.Factory.StartNew(async () => {

                await CopyDocToDirectory(doc);

            })

        )).Wait();

    }

    public static void Main()

    {

        var docsList = new List<string>();

        for(var i = 0; i < 10; i++)

            docsList.Add(string.Format("TestFile{0}", i));

        ProcessDocsAndCopyToDirectory(docsList);

        foreach(var file in docsList)

            Console.WriteLine("File {0} was readed", file);

        Thread.Sleep(20000);

    }

}