OptionalbodyOptionalheadersOptionalmaxHard cap on the response body size in bytes; the request aborts if exceeded.
OptionalsignalAborted when the engine's overall deadline (timeoutMs) passes. A transport should stop
the request then (fetch(url, { signal })); the engine rejects at the deadline either way,
and enforces maxResponseBytes on the body it gets back, so neither limit depends on it.
OptionaltimeoutPer-request timeout in milliseconds.
Fully-qualified absolute URL.
Optional request body (already serialised).