Key value to access the user-defined pointer associated with a connection using SASL EXTERNAL authentication method.

Use vortex_connection_set_data and vortex_connection_get_data to access the data.

This data is configured at vortex_sasl_accept_negotiation_full, and then passed to the handler configured. Because the SASL module doesn't remove this data once the authentication process have finished, you can still get access to the data configured using this key.