thread_pool_count = 0 (default) keeps handlers inline on the loop
thread — the measured fast path (BENCH-HTTPZ.md). N > 0 dispatches
each parsed request to a std.thread Pool of N workers, completing the
httpz two-pool shape: the connection freezes as CONN_HANDLING (no
reads, growth, eviction, or recycling — the worker borrows views into
its read buffer), the worker runs the handler under a per-job arena
and serializes into job-owned bytes, the completion queues under the
PoolState mutex, and the loop wakes through the new std.event wake
channel (kqueue EVFILT_USER + EV_CLEAR; the epoll twin maps to
eventfd), attaches the response, compacts the buffer, and resumes
keep-alive/pipeline handling. A full backlog sheds with 503. Stale
completions (generation mismatch after close) are dropped. Pool mode
requires the server's constructing allocator to be thread-safe
(GPA/malloc), documented on the knob.
PoolState lives behind a heap pointer (it embeds a Mutex and is shared
with workers; the Server struct itself is returned by value).
serialize_response/run_handler_job share one serialize_bytes.
examples/1633 gains the pooled section (GET, body echo, 404 across
worker threads) plus the loop-wake path exercised end to end; AOT run
five times. examples/1632 unchanged but the Event struct gains `user`.
Loop.init/close, add_read/del_read/add_write/del_write with a
per-registration udata word, and wait() normalizing backend events
into Event{fd, udata, readable, writable, eof, err, nbytes}. The epoll
twin (S4) slots in behind this surface when the linux target lands.
No timer registrations by design: request/keepalive eviction is
deadline math — deadline_in/expired/remaining_ms over std.time's
monotonic clock, with remaining_ms feeding wait's timeout. std.sx
barrel carries ; .ir snapshot regen is the usual mechanical
renumbering. examples/1632 pins idle timeout (and that it honors the
deadline), readable with fd/udata/nbytes, immediate writability on an
empty send buffer, and the eof flag on peer close; JIT + AOT.
