Hmm, the pre-computed header strings is definitely interesting optimization, and does seem to be a bit non-idiomatic – but IMO, this is the sort of optimization

Hmm, the pre-computed header strings is definitely interesting optimization, and does seem to be a bit non-idiomatic – but IMO, this is the sort of optimization the framework itself should try and do. If first several bytes of the header are going to identical for many requests, a super-optimized framework would ideally memoize it, and write it directly out, as this benchmark is doing. (And if the framework itself is doing it, then any user of the benchmark would just inherit that optimization, and not have to resort to non-idiomatic optimizations...)