Replace the rewrite requirement check with a BodyResponseModifier
marker and treat header and body modifiers separately.
This ensures header/status rewrites still apply when body rewriting is
blocked (for binary, encoded, or chunked responses), while body changes
are skipped safely. It also avoids body reset/close side effects and
returns early on passthrough responses.
Update middleware tests to cover split header/body behavior and themed
middleware body-skip scenarios.
Prevent response modifiers that require body rewriting from running when
the body rewrite gate blocks buffering (for example, chunked transfer
encoding).
Add an explicit `requiresBodyRewrite` capability and implement it for
HTML/theme/error-page modifiers, including bypass delegation.
Also add a regression test to ensure the original response body remains
readable and is not closed prematurely when rewrite is blocked.
This commit fixeds the "http: read on closed response body" with empty page error
happens when body-rewriting middleware (like themed) runs on responses where body rewrite is blocked (e.g. chunked),
then the gate restores an already-closed original body.
- Remove BytesPoolWithMemory; split into UnsizedBytesPool and 11-tier SizedBytesPool
- Track buffer capacities with xsync Map to prevent capacity leaks
- Improve buffer reuse: split large buffers and put remainders back in pool
- Optimize small buffers to use unsized pool
- Expand test coverage and benchmarks for various allocation sizes
