The gateway built an httpx.AsyncClient for every request, so each page paid a
fresh TCP and TLS handshake to the upstream. With surya_instances: 24 that is
24 streams reconnecting per page, against a round trip that already dominates
the cost of reading one.

One pooled client with keep-alive instead, so a document's pages reuse the
connection. Correctness-neutral; it only ever cost time.

Keyed by the event loop, because an AsyncClient binds to the loop that created
it and coderai runs more than one (the OCR pool keeps its own). The key is the
loop OBJECT held weakly, not id(): keying by id would leak an entry per dead
loop and, since CPython reuses addresses, could hand a new loop a client bound
to the closed one that used to live at that address — a fault that would only
appear under the load this change exists to handle.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PxYHWbCAjjjD7A1rhFKtaW