title: In Tornado, how to do non-blocking file read/write?
body: <p>I've been using Tornado for a while now and I've encountered issues with slow timing (which I asked about in <a href="https://stackoverflow.com/questions/38530886/why-do-long-http-round-trip-times-stall-my-tornado-asynchttpclient">this question</a>). One possible issue that was pointed out by a fellow user was that I was using regular <code>open("..." , 'w')</code> to write to files in my co-routine and that this might be a blocking piece of code.</p>
  
  <p>So my question is, is there a way to do non-blocking file IO in Tornado? I couldn't find anything in my research that fit my needs.</p>