x509.serialNumber
此证书的序列号。
¥The serial number of this certificate.
序列号由证书颁发机构分配，不能唯一标识证书。考虑使用 x509.fingerprint256 作为唯一标识符。
¥Serial numbers are assigned by certificate authorities and do not uniquely
identify certificates. Consider using x509.fingerprint256 as a unique
identifier instead.