src/Security/CSRF.php
protected function ivalidateToken($index, array &$tokenStorage)
    {
        unset($tokenStorage[$index]);
        $this->session->set(self::SESSION_KEY, $tokenStorage);
    }
protected function ivalidateToken($index, array &$tokenStorage)
    {
        unset($tokenStorage[$index]);
        $this->session->set(self::SESSION_KEY, $tokenStorage);
    }
Invalidates the specific token by unsetting it from the tokenStorage
array in the session.
@param string $index Token index
@param array $tokenStorage Token storage array with all tokens