title: Express.js connect-timeout. how to handle when timout fire,where it generate error
body: <p>When I use the connect-timeout when timeout fire, it shows </p>
  
  <pre><code>[2015-07-31 11:46:18.983] [ERROR] console - ServiceUnavailableError:
  Response timeout
        at IncomingMessage. (/opt/data/nlb-server-dev/node_modules/connect-timeout/index.js:69:8)
        at IncomingMessage.EventEmitter.emit (events.js:95:17)
        at null._onTimeout (/opt/data/nlb-server-dev/node_modules/connect-timeout/index.js:41:11)
      at Timer.listOnTimeout as ontimeoutenter
  [2015-07-31 11:46:18.990] [ERROR] exception-log - Server web-server-1: Caught
  exception: Error: Can't set headers after they are sent. stack: Error:
  Can't set headers after they are sent.   at
  ServerResponse.OutgoingMessage.setHeader (http.js:691:11)    at
  ServerResponse.res.set.res.header
  (/opt/data/nlbserverdev/node_modules/express/lib/response.js:561:10)  
  at ServerResponse.res.send
  (/opt/data/nlbserverdev/node_modules/express/lib/response.js:133:12)
  at ServerResponse.res.json
  (/opt/data/nlb-server-dev/node_modules/express/li
  b/response.js:210:15)at ServerResponse.res.send
  (/opt/data/nlb-server-dev/node_modules/express/lib/response.js:121:21)
  at /opt/data/nlb-server-dev/app/services/web/adminHandler.js:110:9 at
  Object.utils.invokeCallback
  (/opt/data/nlb-server-dev/app/util/utils.js:9:8) at
  /opt/data/nlb-server-dev/app/dao/baseDao.js:48:13 at Query._callback
  (/opt/data/nlb-server-dev/app/dao/mysql/mysql.js:55:9) at
  Query.Sequence.end
  (/opt/data/nlb-server-dev/node_modules/mysql/lib/proto
  col/sequences/Sequence.js:78:24)
  </code></pre>
  
  <p>I handle  with it as follows, but it does not work</p>
  
  <pre><code>function errorFilter(err, req, res, next){
    logger.warn(err.stack);
    errcode = err.statusCode || 500;
    msg = err.message || 'server error!';
    res.send(errcode, msg);
  }
  </code></pre>
  
  <p>I see the middiwire I can't find how do handle it. Please help me.</p>