The BI Connector uses the local address of a Connection to filter current operations on the server. The new Connection interface does not provide access to the underlying net.Conn's local address. This ticket should add a LocalAddresser interface to the driver package that has a LocalAddress() method. It can return a net.Addr or a string; the BIC only needs the address as a string:

c, err := server.Connection(ctx)
connAddrs = append(connAddrs, c.LocalAddr().String())

so returning a string directly is fine (we would just skip the trailing .String() call).

The old version of the go driver used by BI Connector had a LocalAddr method on the Connection type that returned a net.Addr which was just the underlying net.Conn's LocalAddr() result.