An X509 certificate (e.g. for TLS).
The X509Certificate class represents an X509 certificate. Certificates can be loaded and saved like any other [Resource]. They can be used as the server certificate in [method StreamPeerTLS.accept_stream] (along with the proper [CryptoKey]), and to specify the only certificate that should be accepted when connecting to a TLS server via [method StreamPeerTLS.connect_to_stream].
$DOCS_URL/tutorials/networking/ssl_certificates.html
Loads a certificate from [param path] ("*.crt" file).
Loads a certificate from the given [param string].
Saves a certificate to the given [param path] (should be a "*.crt" file).
Returns a string representation of the certificate, or an empty string if the certificate is invalid.