sync.Pool for bytes.Buffer to reduce allocations in hot paths

For high-throughput endpoints that serialize JSON or build strings repeatedly, allocations can become a real cost. sync.Pool is a pragmatic tool for reusing temporary buffers without manual free lists. The key is to treat pooled objects as ephemeral: get a buffer, Reset it, use it, and return it. Never store pooled pointers long-term. The pool can drop objects at any time, which is fine because it’s a performance hint, not a correctness mechanism. In production, I use this for response building, log formatting, and compression pipelines where buffers are short-lived and frequently reused. It won’t fix slow algorithms, but it can significantly reduce allocs/op once you’ve identified a hot loop. Pair it with benchmarks so you can confirm the improvement.