use https://gist.github.com/J-kit/077c0bcba996cdb32602895e73237f59

YoutubeProvider-usage.cs

public static void use(string[] args)
        {
            var dat = new YoutubeProvider(args.Length != 0 ? args[0] : "https://www.youtube.com/watch?v=IxuEtL7gxoM");
            var dat1 = new YoutubeProvider(args.Length > 1 ? args[1] : "https://www.youtube.com/watch?v=VmUGe8KDdGI");

            while (!dat.hasFinished || !dat1.hasFinished)
            {
                WaitHandle.WaitAny(new[] { dat.waiter, dat1.waiter }, -1);
                // dat.WaitOne(); for one or "WaitHandle.WaitAny(new[] { dat.waiter, dat1.waiter }, -1);" for multible downloads 
                Console.WriteLine("1: {0}%, {1} secs remaining", dat.percentage.ToString("0.0"), dat.eta.TotalSeconds);
                Console.WriteLine("2: {0}%, {1} secs remaining", dat1.percentage.ToString("0.0"), dat1.eta.TotalSeconds);
            }

            File.WriteAllText(dat.saveto + ".log", dat.rawResponse);
            Console.WriteLine("Finished");
            Console.ReadLine();
        }