title: Efficient compression of folder with same file copied multiple times
body: <p>I am creating a <code>*.zip</code> using Ionic.Zip. However, my <code>*.zip</code> contains same files multiple times, sometimes even 20x, and the <strong>ZIP</strong> format does not take advantage of it at all.</p>
  
  <p>Whats worse, Ionic.Zip sometimes crashes with an <code>OutOfMemoryException</code>, since I am compressing the files into a <code>MemoryStream</code>.</p>
  
  <p>Is there a <strong>.NET</strong> library for compressing that takes advantage of redundancy between files?</p>
  
  <p>Users decompress the files on their own, so it cannot be an exotic format.</p>