util: implement debounce

[jasnell]

I found myself using debounce quite a bit recently while testing some recent other additions (quic and dtls testing, perf_hooks improvements, etc). I was using an npm dependency right up until I realized just how generally useful it is to actually have it Just There. So, since it was a holiday and I just felt like it... util.debounce(...)

const fn = util.debounce(() => console.log(123), 1000);

fn();  // starts the timer... will invoke the inner fn
       // after 1 second if fn() is not called again

await setTimeout(500);

fn();  // calling it again before the invocation resets the timer.

[codecov]

Codecov Report

❌ Patch coverage is 99.48454% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 90.17%. Comparing base (72c1fea) to head (459f1a0).
⚠️ Report is 7 commits behind head on main.

Files with missing lines	Patch %	Lines
lib/internal/util/debounce.js	99.45%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##             main   #65899    +/-   ##
========================================
  Coverage   90.17%   90.17%            
========================================
  Files         771      772     +1     
  Lines      265097   265291   +194     
  Branches    50355    50393    +38     
========================================
+ Hits       239040   239234   +194     
- Misses      17009    17016     +7     
+ Partials     9048     9041     -7     

Files with missing lines	Coverage Δ
lib/util.js	100.00% <100.00%> (ø)
lib/internal/util/debounce.js	99.45% <99.45%> (ø)

... and 34 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[ljharb]

what's the userland precedent for an AbortSignal-aware debounce implementation?