private static void AddFileToZip(string zipFilename,
                                         string fileToAdd,
                                         CompressionOption compression = CompressionOption.Normal)
        {
            System.Uri uri;
            System.IO.Packaging.PackagePart part;

            using (System.IO.Packaging.Package zip = System.IO.Packaging.ZipPackage.Open(zipFilename, System.IO.FileMode.OpenOrCreate))
            {
                uri = System.IO.Packaging.PackUriHelper.CreatePartUri(new System.Uri(".\\" + new System.IO.FileInfo(fileToAdd).Name, System.UriKind.Relative));
                if (zip.PartExists(uri))
                {
                    zip.DeletePart(uri);
                }

                part = zip.CreatePart(uri, "", System.IO.Packaging.CompressionOption.Normal);
                using (System.IO.FileStream fileStream = new System.IO.FileStream(fileToAdd, System.IO.FileMode.Open, System.IO.FileAccess.Read, System.IO.FileShare.Read, 8192))
                {
                    using (System.IO.Stream dest = part.GetStream())
                    {
                        fileStream.CopyTo(dest, 8192); // <<< ВОТ ТУТ ЕМУ ЧТО НАДО ЕЩЕ
                        dest.Close();
                    }
                    fileStream.Close();
                }

            }
        }