createTransport doesn't respect the use of "0" as a port number
See https://cloud-haskell.atlassian.net/browse/DPSLN-9. If we pass "0" as the port (which means "pick an arbitrary free port"), the endpoint addressing will break, because instead of checking which port was actually assigned, we store "0" as our port number. This breaks d-p-simplelocalnet, for example.
The simplest fix would be to disallow "0" as a port number, although that's perhaps not the most user-friendly thing to do.
Bumping this to the next release. Sorry about that.