public function queryBroadcastMessageStatus ($broadcastMessageID)
    {
        $json = json_decode(
            $this->client->send(
                new Request(
                    "POST",
                    "https://api.weixin.qq.com/cgi-bin/message/mass/get",
                    [],
                    json_encode(
                        [
                            "msg_id" => (int)$broadcastMessageID,
                        ]
                    )
                )
            )->getBody()
        );

        return strtolower($json->msg_status);
    }