[ofw] WinVerbs CQ events

[Sean Hefty]

>I thought that when working with events the flow is (1) post receive (2) wait
>for completion and only than (3) poll.

I was referring to rearming the CQ.  If it occurs between steps 2 and 3 above,
then I would either expect poll to pull 2 work completions in Prasanna's case,
or see 2 events.  If the rearm occurs after step 3, then what happens (see
below)?

>In any case the hca will create an event if (it hasn't already done that) if
>there is a new CQE that the driver has not seen.

To clarify my question, will the following generate a second event?

message is received
CQ event is generated
ibv_poll_cq returns 1 completion
message is received
ibv_req_notify_cq to rearm CQ

I think the answer is yes for Mellanox HW, but want to be sure on Windows.