Add async_antiflood helper for AsyncTeleBot

[Dramex]

telebot.util.antiflood() wraps a sync call in a retry loop that honours Telegram's retry_after parameter on 429 responses. AsyncTeleBot users have no equivalent, so every async bot re-implements the same loop around asyncio.sleep and ApiTelegramException.

This adds async_antiflood() next to the sync one in telebot.util. Same signature, same retry budget semantics, but awaits function(*args, **kwargs) and sleeps via asyncio.sleep. Drop-in for an async bot:

from telebot.util import async_antiflood

for chat_id in chat_ids:
    await async_antiflood(bot.send_message, chat_id, text)

Behaviour

Mirrors the sync version exactly:

• Non-429 ApiTelegramException propagates immediately, no retry.
• 429 responses sleep for the server-supplied retry_after seconds, then retry, up to number_retries - 1 times.
• The final attempt runs without the 429 guard, so an exhausted budget surfaces the last exception to the caller.

Tests

Four new tests in tests/test_async_telebot.py:

• returns on first success without sleeping
• single 429 retries exactly once after sleeping retry_after seconds
• non-429 error propagates without retrying
• after number_retries attempts the last 429 surfaces

All five tests in the file pass (the earlier strong-ref test from #2588 plus the four new ones).

Notes

• async_antiflood imports ApiTelegramException and asyncio lazily at call time, same style the sync helper uses, so telebot.util keeps its import graph clean.
• Exported from telebot.util.__all__.

[Copilot]

Pull request overview

Adds an async equivalent of telebot.util.antiflood() for AsyncTeleBot, enabling retry-on-429 behavior that honors Telegram’s retry_after parameter without requiring each async bot to re-implement the loop.

Changes:

• Introduce telebot.util.async_antiflood() mirroring antiflood() semantics for async callables.
• Export async_antiflood via telebot.util.__all__.
• Add unit tests covering success, 429 retry/sleep behavior, non-429 propagation, and retry budget exhaustion.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
telebot/util.py	Adds async_antiflood() and exports it in __all__.
tests/test_async_telebot.py	Adds test cases validating async_antiflood() behavior.

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[Badiboy]

LGTM. @coder2020official ?