File Stream C#

using System;
using System.Collections.Generic;
using System.Text;
using System.Diagnostics;
using System.Windows.Forms;
using System.IO.Compression;
public class Utils
{
    public static int ReadAllBytesFromStream(GZipStream stream, ref string destination)
    {
        // Use this method is used to read all bytes from a stream.
        int offset = 0;
        int totalCount = 0;
        byte[] buffer = new byte[100];
        StringBuilder str = new StringBuilder();
        while (true)
        {
            int bytesRead = stream.Read(buffer, offset, 100);
            if (bytesRead == 0)
            {
                break;
            }
            str.Append(System.Text.Encoding.ASCII.GetString(buffer));
            offset += bytesRead;
            totalCount += bytesRead;
        }
        destination = str.ToString();
        return totalCount;
    }
}