title: NodeJS get a count of bytes of streaming file download
body: <p>In this code I stream a file from a url and save it to a file. Is there a way to also pipe it through something that will count the number of bytes piped? (Which would tell me the file size.)</p>
  
  <pre><code>  request.stream(url)
      .pipe(outputFile)
  </code></pre>
  
  <p>Is there some library that would do this by piping the download through it, or a simple way for me to do it myself?</p>