ProgressFileStream.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace denPusher
{
    public class ProgressFileStream : FileStream
    {
        public event EventHandler<long> ProgressChanged;
        private long totalRead = 0;

        public ProgressFileStream(string path, FileMode mode) : base(path, mode)
        {
        }

        public override int Read(byte[] array, int offset, int count)
        {
            var bytesRead = base.Read(array, offset, count);
            totalRead += bytesRead;
            ProgressChanged?.Invoke(totalRead, this.Length);
            return bytesRead;
        }

        public override void Write(byte[] array, int offset, int count)
        {
            base.Write(array, offset, count);
            OnProgressChanged(count);
        }


        protected virtual void OnProgressChanged(long bytes)
        {
            ProgressChanged?.Invoke(this, bytes);
        }
    }
}