title: keep alive errors seen in nginx logs
body: <p>In <code>var/log/nginx/https-error_log</code> and <code>var/log/nginx/http-error_log</code>, I see tens of millions of errors (aggregated over the past several months):</p>
  
  <pre><code>client xx.xx.xxx.xxx closed keepalive connection
  </code></pre>
  
  <p>Frequently (but not always) they exist in pairs with the same IP address and timestamp even, e.g.:</p>
  
  <pre><code>2016/07/12 19:24:59 [info] 44815#0: *82924 client 82.145.210.66 closed keepalive connection
  2016/07/12 19:24:59 [info] 44821#0: *83275 client 82.145.210.66 closed keepalive connection
  </code></pre>
  
  <p>I.e. it seems the same person closed the connection twice at the same point in time? I feel something untoward is going on here. I'm using nginx as a reverse proxy in front of gunicorn (it's a Django app). Can anyone with expertise help me troubleshoot this issue, or speculate what it could be? Alternatively, is it something I shouldn't worry about?</p>