A callback invoked after each attempt completes with the elapsed
durationMs and parsed rateLimit headers when present. When the response
was served from the opt-in response cache, cacheHit is true and
durationMs is 0; when a cacheable read was served from the network
after a cache miss, cacheHit is false. Responses unrelated to the
cache (mutations, cache-less clients) carry no cacheHit at all. When the
request waited for rate-limit pacing before dispatch, pacedMs carries
the total time spent waiting across the request's attempts, cumulative,
so on a retried request it can exceed the final attempt's durationMs
(which measures only that attempt); requests that never waited carry no
pacedMs at all.
A callback invoked after each attempt completes with the elapsed
durationMsand parsedrateLimitheaders when present. When the response was served from the opt-in response cache,cacheHitistrueanddurationMsis0; when a cacheable read was served from the network after a cache miss,cacheHitisfalse. Responses unrelated to the cache (mutations, cache-less clients) carry nocacheHitat all. When the request waited for rate-limit pacing before dispatch,pacedMscarries the total time spent waiting across the request's attempts, cumulative, so on a retried request it can exceed the final attempt'sdurationMs(which measures only that attempt); requests that never waited carry nopacedMsat all.