src/PicoAuthPlugin.php
protected function checkLogoutSubmission()
    {
        $post = $this->request->request;
        if ($post->has("logout")) {
            if (!$this->isValidCSRF($post->get("csrf_token"), self::LOGOUT_CSRF_ACTION)) {
                $this->redirectToPage("logout");
            }
            $this->logout();
        }
    }
protected function checkLogoutSubmission()
    {
        $post = $this->request->request;
        if ($post->has("logout")) {
            if (!$this->isValidCSRF($post->get("csrf_token"), self::LOGOUT_CSRF_ACTION)) {
                $this->redirectToPage("logout");
            }
            $this->logout();
        }
    }
Checks the current request for logout action