socket.io - xhr-polling disconnects automatically

I made simple app using socket.io and the xhr-polling transport.
I found out that the server disconnect me after several seconds I stay connected.

This issue happens only with xhr-polling transport..
How can I fix that? am I missing something?

From: https://github.com/LearnBoost/Socket.IO/wiki/Configuring-Socket.IO

SERVER OPTIONS

polling duration: defaults to 20 seconds

The maximum duration of one HTTP poll, if it exceeds this limit it will be closed.