Adds speed/time remaining to the ProgressChangedEventArgs of a webclient

SpeedyClient.cs

using System;
using System.Net;
using System.ComponentModel;
using System.Diagnostics;

namespace SpeedClient
{
    public delegate void SpeedyDownloadProgressChangedEventHandler(SpeedyDownloadProgressChangedEventArgs e);
    public delegate void SpeedyUploadProgressChangedEventHandler(SpeedyUploadProgressChangedEventArgs e);

    public sealed class SpeedyClient : WebClient
    {
        private Stopwatch Counter;

        public event SpeedyDownloadProgressChangedEventHandler SpeedyDownloadProgressChanged;
        public event SpeedyUploadProgressChangedEventHandler SpeedyUploadProgressChanged;

        public SpeedyClient()
        {
            Counter = new Stopwatch();
        }

        protected override WebResponse GetWebResponse(WebRequest request, IAsyncResult result)
        {
            Counter.Reset();
            Counter.Start();
            return base.GetWebResponse(request, result);
        }

        protected override void OnDownloadProgressChanged(DownloadProgressChangedEventArgs e)
        {
            base.OnDownloadProgressChanged(e);
            if (SpeedyDownloadProgressChanged == null) return;
            SpeedyDownloadProgressChanged(new SpeedyDownloadProgressChangedEventArgs(e, Counter.ElapsedMilliseconds));
        }
        
        protected override void OnUploadProgressChanged(UploadProgressChangedEventArgs e)
        {
            base.OnUploadProgressChanged(e);
            if (SpeedyUploadProgressChanged == null) return;
            SpeedyUploadProgressChanged(new SpeedyUploadProgressChangedEventArgs(e, Counter.ElapsedMilliseconds));
        }
    }

    public class SpeedyDownloadProgressChangedEventArgs : ProgressChangedEventArgs
    {
        public SpeedyDownloadProgressChangedEventArgs(DownloadProgressChangedEventArgs e, long elapsed) : base(e.ProgressPercentage, e.UserState)
        {
            BytesReceived = e.BytesReceived;
            TotalBytesToReceive = e.TotalBytesToReceive;
            BytesLeft = TotalBytesToReceive - BytesReceived;
            BytesPerMillisecond = BytesReceived / elapsed;
            TotalMillisecondsLeft = BytesLeft / BytesPerMillisecond;
        }

        public long BytesReceived { get; private set; }
        public long TotalBytesToReceive { get; private set; }
        public long BytesLeft { get; private set; }
        public long BytesPerMillisecond { get; private set; }
        public long TotalMillisecondsLeft { get; private set; }
    }

    public class SpeedyUploadProgressChangedEventArgs : ProgressChangedEventArgs
    {
        public SpeedyUploadProgressChangedEventArgs(UploadProgressChangedEventArgs e, long elapsed) : base(e.ProgressPercentage, e.UserState)
        {
            BytesReceived = e.BytesReceived;
            BytesSent = e.BytesSent;
            TotalBytesToReceive = e.TotalBytesToReceive;
            TotalBytesToSend = e.TotalBytesToSend;
            BytesLeft = TotalBytesToSend - BytesSent;
            BytesPerMillisecond = BytesSent / elapsed;
            TotalMillisecondsLeft = BytesLeft / BytesPerMillisecond;
        }

        public long BytesReceived { get; private set; }
        public long BytesSent { get; private set; }
        public long TotalBytesToReceive { get; private set; }
        public long TotalBytesToSend { get; private set; }
        public long BytesLeft { get; private set; }
        public long BytesPerMillisecond { get; private set; }
        public long TotalMillisecondsLeft { get; private set; }
    }
}