查询SD卡信息的返回结果

{
    "code": 200,
    "msg": "ok",
    "data": {
        "timestamp": 0,
        "sd_card_status": "OK",
        "sd_total_size_mb": 1000,
        "sd_free_size_mb": 100,
        "sd_recording_mode": 0
    }
}