public static void Copy(Stream source, Stream destination, byte[] buffer, ProgressHandler progressHandler, TimeSpan updateInterval, object sender, string name, long fixedTarget)
 {
     if (source == null)
     {
         throw new ArgumentNullException("source");
     }
     if (destination == null)
     {
         throw new ArgumentNullException("destination");
     }
     if (buffer == null)
     {
         throw new ArgumentNullException("buffer");
     }
     if (buffer.Length < 0x80)
     {
         throw new ArgumentException("Buffer is too small", "buffer");
     }
     if (progressHandler == null)
     {
         throw new ArgumentNullException("progressHandler");
     }
     bool continueRunning = true;
     DateTime now = DateTime.Now;
     long processed = 0L;
     long target = 0L;
     if (fixedTarget >= 0L)
     {
         target = fixedTarget;
     }
     else if (source.CanSeek)
     {
         target = source.Length - source.Position;
     }
     ProgressEventArgs e = new ProgressEventArgs(name, processed, target);
     progressHandler(sender, e);
     bool flag2 = true;
     while (continueRunning)
     {
         int count = source.Read(buffer, 0, buffer.Length);
         if (count > 0)
         {
             processed += count;
             flag2 = false;
             destination.Write(buffer, 0, count);
         }
         else
         {
             destination.Flush();
             continueRunning = false;
         }
         if ((DateTime.Now - now) > updateInterval)
         {
             flag2 = true;
             now = DateTime.Now;
             e = new ProgressEventArgs(name, processed, target);
             progressHandler(sender, e);
             continueRunning = e.ContinueRunning;
         }
     }
     if (!flag2)
     {
         e = new ProgressEventArgs(name, processed, target);
         progressHandler(sender, e);
     }
 }
        /// <summary>
        /// Copy the contents of one <see cref="Stream"/> to another.
        /// </summary>
        /// <param name="source">The stream to source data from.</param>
        /// <param name="destination">The stream to write data to.</param>
        /// <param name="buffer">The buffer to use during copying.</param>
        /// <param name="progressHandler">The <see cref="ProgressHandler">progress handler delegate</see> to use.</param>
        /// <param name="updateInterval">The minimum <see cref="TimeSpan"/> between progress updates.</param>
        /// <param name="sender">The source for this event.</param>
        /// <param name="name">The name to use with the event.</param>
        /// <param name="fixedTarget">A predetermined fixed target value to use with progress updates.
        /// If the value is negative the target is calculated by looking at the stream.</param>
        /// <remarks>This form is specialised for use within #Zip to support events during archive operations.</remarks>
        public static void Copy(Stream source, Stream destination,
            byte[] buffer,
            ProgressHandler progressHandler, TimeSpan updateInterval,
            object sender, string name, long fixedTarget)
        {
            if (source == null) {
                throw new ArgumentNullException("source");
            }

            if (destination == null) {
                throw new ArgumentNullException("destination");
            }

            if (buffer == null) {
                throw new ArgumentNullException("buffer");
            }

            // Ensure a reasonable size of buffer is used without being prohibitive.
            if (buffer.Length < 128) {
                throw new ArgumentException("Buffer is too small", "buffer");
            }

            if (progressHandler == null) {
                throw new ArgumentNullException("progressHandler");
            }

            bool copying = true;

            DateTime marker = DateTime.Now;
            long processed = 0;
            long target = 0;

            if (fixedTarget >= 0) {
                target = fixedTarget;
            }
            else if (source.CanSeek) {
                target = source.Length - source.Position;
            }

            // Always fire 0% progress..
            ProgressEventArgs args = new ProgressEventArgs(name, processed, target);
            progressHandler(sender, args);

            bool progressFired = true;

            while (copying) {
                int bytesRead = source.Read(buffer, 0, buffer.Length);
                if (bytesRead > 0) {
                    processed += bytesRead;
                    progressFired = false;
                    destination.Write(buffer, 0, bytesRead);
                }
                else {
                    destination.Flush();
                    copying = false;
                }

                if (DateTime.Now - marker > updateInterval) {
                    progressFired = true;
                    marker = DateTime.Now;
                    args = new ProgressEventArgs(name, processed, target);
                    progressHandler(sender, args);

                    copying = args.ContinueRunning;
                }
            }

            if (!progressFired) {
                args = new ProgressEventArgs(name, processed, target);
                progressHandler(sender, args);
            }
        }