Fix send_all on eio

[ComanderP]

Was trying the bindings on eio and for some reason Zmq_eio.Socket.send_all wasn't working at all, but Zmq_eio.Socket.send was. Checked the source code and I suppose the wrong argument was given inside the function (do correct me if I'm wrong).
It finally works with the change locally built on my machine (at least I think so).

[andersfugmann]

The messages argument is important, as the send_all should be fully completed (i.e. all messages sent) before continuing.

[andersfugmann]

That definitely seems like an error - but I think the fix is incomplete. Thanks for raising this!

The messages to be sent needs to happen as part of the function. I've added suggestions (although I'm not sure they work as expected). Also I think the tests needed to be extended to verify send_all and recv_all.

[ComanderP]

I've added your suggestions to the pull request.
For the tests, I'm not sure if I'm the right person to do them 😅, but I can surely try if someone gives me some guidance.

(Sorry for the force push, was amending the commit message)

[andersfugmann]

Tests should be added to eio_zmq/test/test.ml. A simple test that verifies that send_all followed by a receive_all works as expected. Look at test_send_receive. However that test uses the send and recv functions defined in the test, which in terms calls Zmq_eio.Socket.send, so you will need to call Zmq_eio.Socket.send_all and Zmq_eio.Socket.recv_all function directly.

[ComanderP]

Done.
There was a repeated usage of the 1st send/receive test test_send_receive which I replaced with the new test (I assume that was a typo).

[andersfugmann]

Looks good. Thanks for doing this. I'll merge once the CI tests passes

[andersfugmann]

Thanks