Headers kept its name/value pairs in a string array and read every element
through scr_arr_get_ref (index checks, retain, release). forEach and the
iterators re-sorted and rescanned the whole list for every step, and every
Response or Headers built from another Headers object re-validated and
re-normalized each copied pair. The Hono fixture spends 12-15% of a request
there.
- Pair loops read borrowed elements of the dense array (sf_pair_at).
- The sort-and-combine list is cached on the Headers object and dropped by
every mutation, so live iteration keeps Node's semantics.
- get() of a single value returns the stored string.
- Copying a Headers object whose pairs are canonical (built by the
constructor or a Response) into an empty list copies the pairs; wire
response headers keep the per-pair path because they may repeat names.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
