Small speed up to frequently called datetime functions

[bdraco]

Proposed change

We call time functions as much as 10000-20000 times per minute so any savings here makes a difference with latency (these are mostly in the bluetooth advertisement path).

We can reduce some python overhead and make functions with static arguments ~30% faster by wrapping them as a partial which avoids the overhead of constructing the underlying call every time since it will only be done once

https://github.com/python/cpython/blob/4b4e6da7b53f9eb2d3654d321f6acfbd599bd990/Modules/_functoolsmodule.c#L286

% cat timer.py
import timeit

print(timeit.timeit("utcnow()", setup="from tester import utcnow"))
print(timeit.timeit("utcnow_partial()", setup="from tester import utcnow_partial"))
% python3 timer.py
0.207963207969442
0.14283533301204443
% cat tester.py
from functools import partial
import datetime as dt

UTC = dt.timezone.utc

def utcnow() -> dt.datetime:
    """Get now in UTC time."""
    return dt.datetime.now(UTC)

utcnow_partial = partial(dt.datetime.now, UTC)

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New integration (thank you!)
• New feature (which adds functionality to an existing integration)
• Deprecation (breaking change to happen in the future)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Additional information

• This PR fixes or closes issue: fixes #
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[bdraco]

Its hitting the event rearm
DEBUG:homeassistant.helpers.event:Called 161.467664 seconds too early, rearming

[bdraco]

Thanks