public function addTemplate($name, $url, $ttl, array $blocks, array $metadata)
    {
        $this->templates[$name] = [
            'url' => $url,
            'ttl' => $ttl,
            'blocks' => $blocks,
            'metadata' => $metadata,
            'checked_ttl' => false,
            'checking_ttl' => false,
        ];
    }