BaseProactorEventLoop._loop_self_reading() uses an overlapped read of 4096 bytes. I don't understand how it wakes up the event loop. When the operation is done, _loop_self_reading() is scheduled with call_soon() by the Future object. Is it enough to wake up the event loop?

Is BaseProactorEventLoop correct?

--

Oh, I forgot to explain this part of asyncio_read_from_self.patch:

+                data = self._ssock.recv(4096)
+                if not data:
+                    break

This break "should never occur". It should only occur if _ssock is no more blocking. But it would be a bug, because this pipe is private and set to non-blocking at its creation.

I chose to add the test because it should not hurt to add it "just in case" (and to avoid an unlimited busy loop).