title: callback to handle completion of pipe
body: <p>I am using the following node.js code to download documents from some url and save it in the disk.
  I want to be informed about when the document is downloaded. i have not seen any callback with pipe.Or, Is there any 'end' event that can be captured on completion of download ?</p>
  
  <pre><code>request(some_url_doc).pipe(fs.createWriteStream('xyz.doc'));
  </code></pre>