public int WriteData(string fName, int offset, string data)
        {
            string[] file = fName.Split('.');
            try
            {
                byte[] bytes = new byte[data.Length];
                bytes = Encoding.UTF8.GetBytes(data);
                fileStream.Seek(offset, SeekOrigin.Begin);
                fileStream.Write(bytes, 0, bytes.Length);
            }
            catch (Exception ex)
            {
                return 1;
            }
            return 0;
        }