Connect Tableau to MySQL datasource using Gateway and Private Key

Because of firewall (IP) restrictions, a data source will not permit a server+username+password connection to its MySQL database. However, the source permits a connection using a Gateway (host+port+username+password) and Gateway RSA private key. Tableau documentation, however, does not appear to describe a way to use a gateway to connect to a MySQL database. Our requirement is to provide instructions sufficiently detailed that we can connect Tableau to the MySQL database via a gateway.