tlsSocket.getPeerX509Certificate()
将对等证书作为 <X509Certificate> 对象返回。
🌐 Returns the peer certificate as an <X509Certificate> object.
如果没有对等证书，或者套接字已被销毁，将返回 undefined。
🌐 If there is no peer certificate, or the socket has been destroyed,
undefined will be returned.