title: How to stream to/from a file descriptor in node?
body: <p>The <code>fs.createReadStream()</code> and <code>fs.createWriteStream()</code> only support file <em>paths</em> but I need to read (or write) from a file descriptor (passed to/from a child process).</p>
  
  <p>Note I need Streams, so <code>fs.open/fs.read/fs.write</code> are not sufficient.</p>