TlsConnection.setCertificate

This sets the certificate that conn will present to its peer during the TLS handshake. For a #GTlsServerConnection, it is mandatory to set this, and that will normally be done at construct time.

For a #GTlsClientConnection, this is optional. If a handshake fails with [gio.types.TlsError.CertificateRequired], that means that the server requires a certificate, and if you try connecting again, you should call this method first. You can call [gio.tls_client_connection.TlsClientConnection.getAcceptedCas] on the failed connection to get a list of Certificate Authorities that the server will accept certificates from.

(It is also possible that a server will allow the connection with or without a certificate; in that case, if you don't provide a certificate, you can tell that the server requested one by the fact that [gio.tls_client_connection.TlsClientConnection.getAcceptedCas] will return non-null.)