Pure-JavaScript optimizations to lib/internal/webstreams/* that reduce
per-chunk and per-construction allocations on hot paths without
observable behavior change.
Per-chunk: reuse promise-reaction closures per controller, add buffered
fast path for async iterator, specialize callback wrappers by arity,
and share immutable nil records for writable stream resets.
Per-construction: use queueMicrotask for non-object start results,
materialize reader/writer .closed and .ready records lazily, and remove
dead allocations.
Assisted-by: Claude Fable 5
Signed-off-by: Matteo Collina <hello@matteocollina.com>
PR-URL: https://github.com/nodejs/node/pull/63876
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>
Reviewed-By: Mattias Buelens <mattias@buelens.com>
Reviewed-By: Gürgün Dayıoğlu <hey@gurgun.day>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>