public function addProtocol($protocol)
    {
        if (!\in_array($protocol, [ApiDefinition::PROTOCOL_HTTP, ApiDefinition::PROTOCOL_HTTPS], true)) {
            throw new \InvalidArgumentException(\sprintf('"%s" is not a valid protocol', $protocol));
        }

        if (!\in_array($protocol, $this->protocols, true)) {
            $this->protocols[] = $protocol;
        }
    }