I *think* this is a typo.

Right now, whenever I try upgrading to WS, I get:

    Uncaught TypeError: Object #<Transport> has no method 'setInterval'

Did a quick search for WS.prototype.setInterval and I don't see it anywhere. Removing `this` makes the upgrade work correctly.

---

Also, here's a bit of the server-side code:

```js
var express = require('express'),
    app = express(),
    es = new engine.Server(),
    server = require('http').createServer(app);

server.on('upgrade', function(req, socket, head) {
  es.handleUpgrade(req, socket, head);
});
```