Void startTLS(NetHandle h, [String] certfiles=)
h: The connection handle
certs: An optional list of certificate files for TLS encrypted connections. Each file should contain one or more PEM-encoded certificates for a trusted certification authority. If this list is empty (the default), no certificate verification will be performed on encrypted connections, which is insecure.
Begins TLS encryption on an existing connection equivilant to having set usetls to true when creating it. Useful for secure SMTP connections. This function will fail silently if TLS encryption is already in use on the connection.