Add Debounce, debounced, and throttled to fastcore.aio

[ncoop57]

Summary

This PR introduces async debouncing and throttling utilities to fastcore.aio:

• Debounce — A class that coalesces bursts of calls to a function into a single invocation, firing wait seconds after calls stop (with optional max_wait cap). Supports leading and trailing edge modes, cross-thread safety via call_soon_threadsafe, and works as a descriptor on methods.
• debounced(wait, max_wait=None, leading=False, trailing=True) — A decorator wrapping Debounce for easy use on functions and methods.
• throttled(wait, leading=False) — A convenience decorator equivalent to debounced(wait, max_wait=wait), firing at most once per wait seconds.

Details

• Debounce.__call__ schedules a background task that waits for the quiet period to elapse before firing the latest call.
• flush() runs any pending call immediately; cancel() discards it.
• When used as a method descriptor (__get__/__set_name__), each instance gets its own Debounce bound to partial(self.f, obj).
• Safely handles being called from outside the running event loop via call_soon_threadsafe.

Notes

patch now works on callable objects too, not just functions (needed so it composes with Debounce). Objects have no __code__, so the co_qualname stamping from #821 is skipped for them. To fastaudit, a debounced method therefore shows up under its plain function name, not Class.name, so class-style allowlist entries won't match it.

Minimal repro:

from fastcore.utils import run, patch
from fastcore.aio import debounced
from safepyrun.core import RunPython, allow

class T: pass

@patch
def plain(self:T): return run('echo hi')

@patch
@debounced(0.1)
def deb(self:T): run('echo hi')

allow({T: ['plain', 'deb']})
t,python = T(),RunPython()

await python('t.plain()')   # 'hi' -- entry T.plain matches the stamped frame

await python('t.deb()')     # PermissionError -- the fire never presents as T.deb

[ncoop57]

CI failures are unrelated to these changes.

[ncoop57]

This failed for me since jupyter/solveit is already running in an event loop