PHP+Redis Subscribe. How can I force the script to stop executing when the client connection is closed?

Question

PHP

Good afternoon!
There is a bundle from PHP + Redis (via the php-redis package), server-side events are used for real-time event notification.
Everything is fine, however, when the connection with the user is closed (the user has closed the notification page), the PHP script does not stop running and it hangs in memory.
What can be done to avoid this?