Zero-Alloc

time.Format allocates a fresh string on every S3 GET/HEAD response. Swapping to time.AppendFormat drops that heap escape to zero — measured 32 B/op saved per request on the hottest read path.

The Bolt mindset codified: no heap escapes in hashing/encoding, deadline amortization cuts SetDeadline ~98%, allocation hotspots hunted by profile. Teaches: zero-escape patterns, measurement contracts, trade-off posture.