NetworkInterfaceTL's current set of C++ integration tests do not make use of the baton, which makes detecting issues caused by the interaction between NetworkInterfaceTL and the baton difficult to diagnose. Production usage of NetworkInterfaceTL often does use the baton, so this lack of coverage is significant. We should introduce such tests.

If possible, we should try to reuse test cases rather than duplicating them for baton and non-baton usage.