title: Can't send a zip stream through mail
body: <p>I have a MemoryStream which represents a zip file.
  This is how the stream is created : </p>
  
  <pre><code>var zipMemoryStream = new MemoryStream();
  using (var zipPackage = Package.Open(zipMemoryStream, FileMode.CreateNew))
  {
      foreach (var file in files)
      {
          var c = new Uri("/" + file.FileName + extension, UriKind.Relative);
          var zipPart = zipPackage.CreatePart(c, fileType);
  
          if (zipPart == null)
              continue;
  
          CopyStream(file.MemoryStream, zipPart.GetStream());
      }
  }
  
  File.WriteAllBytes("C:\\ZipTest.zip", zipMemoryStream.ToArray());
  
  try
  {
      mailMsg.Attachments.Add(new Attachment(zipMemoryStream, "ZipTest.zip",
                              MediaTypeNames.Application.Zip));
  }
  </code></pre>
  
  <p>As you can see I have added the line File.WriteAllBytes which saves the stream to my HDD (for testing).</p>
  
  <p>The file which is saved on the HDD is flawless and weights about 138B if the files in the zip are empty.</p>
  
  <p>However, The attachment I get in the mail weights 0B.</p>
  
  <p>Any idea why the attachment weighs 0B?</p>