Sets the TLS validation flags to be used to verify the peer certificate when a TLS connection is established.
GLib guarantees that if certificate verification fails, at least one error will be set, but it does not guarantee that all possible errors will be set. Accordingly, you may not safely decide to ignore any particular type of error.
For example, it would be incorrect to mask EXPIRED if you want to allow expired certificates, because this could potentially be the only error flag set even if other problems exist with the certificate.
the validation flags.
TRUE if the validation flags are set correctly, or FALSE if this is NULL or is not a TLS connection.