title: download a file using windows IStream
body: <p>I'm implementing dragging a virtual file out of a website and onto the desktop with an activex control. </p>
  
  <p>How do I create an <a href="http://msdn.microsoft.com/en-us/library/aa380034(v=VS.85).aspx" rel="nofollow noreferrer">IStream</a> on my http url, so Windows can execute the drop?</p>
  
  <p>The example I'm looking at uses <a href="http://msdn.microsoft.com/en-us/library/bb759864(VS.85).aspx" rel="nofollow noreferrer">SHCreateStreamOnFile</a> to copy a local file; there must be an analogous function for other types of streams like http file download.</p>