隐形reCaptcha响应是私人的

Question

当我var_dump响应不可见的reCaptcha时，success对象是私有的。为什么会这样？

object(ReCaptcha\Response)#22 (3) { ["success":"ReCaptcha\Response":private]=> bool(false) ["errorCodes":"ReCaptcha\Response":private]=> array(1) { [0]=> string(22) "missing-input-response" } ["hostname":"ReCaptcha\Response":private]=> NULL }