SockJS is not closing websockets

First, this issue is related to #127

SockJS is keeping websocket open (readyState == 1) even when the real connect not exists anymore for a long time (hours and days). And, sometimes, sockjs detect it and changes to readyState == 3 (closed) but NOT EMIT 'close' event (or it emit, but listeners did notice that).

I reproduced readyState == 3 bug at development side once, but I dont know how and I couldn't find a way to reproduce it again. I use chrome 27 at OSX

I solved both issue using a simple heart beat (I send a "ping" through websocket, not through a http get/post). On server side I just use a setInterval and close sockets that not sent heart beat for some long time.

I don't know if it a issue related with sockjs, nodejs, fayer or even chrome.

The point is, this issue is causing memory leak, and some applications (like my) needs to know when user leaves.

before: server memory grows from 100mb to 890mb into 2 days.
now: server memory grows from 100mb to 182mb into 2 days.

The issue names no files or tests. Start by reproducing the stale websocket and missing close-event behavior described, comparing it with related issue #127 and the Chrome 27/OS X setup. Done means dead connections are handled and the expected close event is emitted without the reported memory growth.