title: Memory leak introduced when upgrading from Express 3.4 to 3.20?
body: <p>I have been using Express 3.4 with good success for awhile now.</p>
  
  <p>I am not quite ready to make the jump to Express 4 -- However I figure it would be a good idea to upgrade to the latest version of Express 3 prior to jumping off to 4.</p>
  
  <p>So I upgraded my app to use Express 3.20.  </p>
  
  <p>Now:  When I am running my app on express 3.4, the memory usage for each process in pm2 tends to hover around the mid 200, low 300MB range.  </p>
  
  <p>As soon as I upgraded to 3.20, the memory usage started climbing over 600MB in less than an hour for each process, at which point things crash out.</p>
  
  <p>Rolling back to 3.4, I have confirmed that memory usage stays level in the mid-200s.  </p>
  
  <p>Changing express versions is the only modification I have made.  </p>
  
  <p>I am wondering:  Is there a known issue / change of some kind, between 3.4 and 3.20, that could cause a  memory leak?</p>