Slow messages issue and possible solution

Hello,
I have investigated through the “slow messages” issue, I see that there is some sort of problem with sessions already open by other plugins.
I installed “quick chat” and the messages arrives at a really slow rates (1 message check every 30 seconds where the configurations says 1 messege check every two seconds).
I found that if I remove the following code

if(!session_id()) {
session_start();
}

placed on another plugin on “plugins_loaded”, quick chat start to work as expected.

Maybe quick chat is overriding the session or not check if the session has been already started or other plugins has to do some other checks before start a session on their own.

In my opinion the problem is cookie/session related and I hope quick chat team will investigate in this.

For replicate the issue add this code in function.php:

add_action( ‘plugins_loaded’, function(){ session_start(); } );

I hope this will help quick chat to be better and better!

Is there any paid version or services around this plugin?
How can I make an estimation of how many contemporary users can the plugin handle with my server configuration?

Thanks

Marco