gh-106751: Optimize KqueueSelector.select() for many iteration case

[corona10]

• Issue: Optimize XXXSelector for many iterations of the event loop #106751

[corona10]

Similar technique can be adopted.

Benchmark

importtimeitimportosfromselectorsimportKqueueSelector, EVENT_WRITE, EVENT_READkqueue=KqueueSelector()
for_inrange(100):
r, w=os.pipe()
os.write(w, b"a")
kqueue.register(r, EVENT_READ)
elapsed=timeit.timeit(
"selector.select()",
number=100000,
globals={"selector": kqueue},
)
print(f"elapsed: {elapsed}")

Result

AS-IS: elapsed -> 2.3957692080002744
TO-BE: elapsed -> 2.2462058329983847 (1.06x faster)

[eendebakpt]

A minor suggestion. Otherwise looks good.

[bdraco]

Awesome. Thanks for picking up the other ones!