[libfabric-users] Not receiving messages from other ranks

[Hefty, Sean]

> I must have some mistake in my setup of the endpoints, but I just don't know what it
> might be - is there an example anywhere that uses different tx/rx endpoints?

I don't think so.  There's a fi_multi_ep test, but each ep does sends/receives.  We need to add one, because I think this is mostly an untested configuration.

The checks in tcp, udp, and shm are too strong, so would fail fi_enable when they shouldn't.  Checks in other providers I've looked at (rxm, psm2, psm3, sockets, rxd) are missing, which would probably lead to crashes if the endpoints are misconfigured.

Gni doesn't use the utility providers, so any problems it has would be unrelated.

- Sean