Enhance openDir to Respect Buffer Size

[0hmX]

Issue #55764

The current openDir implementation does not fully respect the buffer size. This PR introduces an initial solution based on suggestions from @Ethan-Arrowood. Feedback on the concept would be appreciated.

PR Status

• Ready for merge? (Pending feedback)
• Is passing all the tests

Proposed Solution

I am currently working on a #handlerQueue that stores a readNext function. readNext calls handler.read, and if the return value is not null, it re-adds itself to the queue for continued processing.

Note: This solution might be modified or scrapped, but the aim here is to get the conversation started. And just get the work done.

Current Challenges

1. handler.read does not always populate this.#bufferedEntries—for instance, when a directory is empty. This creates issues with triggering this.processNextHandler after every yield, as it may yield nothing.
2. Determining the appropriate point to return all remaining items.
3. Handling readSync

[Ethan-Arrowood]

Is this working? I'd recommend making the PR a draft until you have the unit tests working.

[codecov]

Codecov Report

Attention: Patch coverage is 87.34177% with 10 lines in your changes missing coverage. Please review.

Project coverage is 88.39%. Comparing base (fe1dd26) to head (d30518b).
Report is 13 commits behind head on main.

Files with missing lines	Patch %	Lines
lib/internal/fs/dir.js	87.34%	10 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #55817      +/-   ##
==========================================
+ Coverage   87.92%   88.39%   +0.46%     
==========================================
  Files         654      654              
  Lines      187815   187871      +56     
  Branches    35830    36140     +310     
==========================================
+ Hits       165139   166063     +924     
+ Misses      15878    15046     -832     
+ Partials     6798     6762      -36     

Files with missing lines	Coverage Δ
lib/internal/fs/dir.js	90.52% <87.34%> (-6.70%)	⬇️

... and 97 files with indirect coverage changes