title: 'GZipStream' could not be found - reference issue
body: <p>I can't get to use GZipStream class in my C# ASP.NET 4.5 application. </p>
  
  <p>I get the error:</p>
  
  <blockquote>
    <p>The type or namespace name 'GZipStream' could not be found (are you missing a using directive or an assembly reference?)</p>
  </blockquote>
  
  <p>I tried using <code>using System.IO;</code> but the <code>System.IO.Compression</code> is not available in the "Reference Manager" in visual studio. I right click on the object name to see if Visual Studio finds the relevant reference but it does not.</p>
  
  <p>Any suggestions?</p>