core-bundle/src/EventListener/CsrfTokenCookieListener.php
public function onKernelRequest(GetResponseEvent $event): void
    {
        if (!$event->isMasterRequest()) {
            return;
        }

        $this->tokenStorage->initialize($this->getTokensFromCookies($event->getRequest()->cookies));
    }
public function onKernelRequest(GetResponseEvent $event): void
    {
        if (!$event->isMasterRequest()) {
            return;
        }

        $this->tokenStorage->initialize($this->getTokensFromCookies($event->getRequest()->cookies));
    }
Reads the cookies from the request and injects them into the storage.