Addition of file to created .Zip archive

FileAddition.cs

				using (ZipArchive zip = ZipArchive.CreateFrom(zipStream, false))
				{
					using (MemoryStream fileStream = new MemoryStream())
					{
						fileStream.Seek(0, SeekOrigin.Begin);

						file.Write(fileStream);

						fileStream.Seek(0, SeekOrigin.Begin);

						zip.AddFile(fileName, fileStream.ToArray());
					}
				}