runtime: make netpoll events sources identifiable on Windows
This is another attempt at CL 558895, but without adding stale pollDescs
protection, which deviates from the original goal of the CL and adds
complexity without proper testing.
It is currently not possible to distinguish between a netpollBreak,
an internal/poll WSA operation, and an external WSA operation (as
in #58870). This can cause spurious wakeups when external WSA operations
are retrieved from the queue, as they are treated as netpollBreak
events.
This CL makes use of completion keys to identify the source of the
event.
While here, fix TestWSASocketConflict, which was not properly
exercising the "external WSA operation" case.
Change-Id: I91f746d300d32eb7fed3c8f27266fef379360d98
Reviewed-on: https://go-review.googlesource.com/c/go/+/561895 Reviewed-by: Than McIntosh <thanm@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: David Chase <drchase@google.com> Reviewed-by: Alex Brainman <alex.brainman@gmail.com>