The inspiration for the post came from my httpz library. The fallback using a FixedBufferAllocator + ArenaAllocator is used. The fixed buffer is a thread local. But the arena allocators belong to connections, of which there could be thousands.

You might have 1 fixed buffer, for N (500+) ArenaAllocators (but only being used per one at a time). This allows you to allocate a relatively large fixed buffer since you have relatively few threads.

If you just used retain_with_limit, then you'd either have to have a much smaller retained size, or you'd need a lot more memory.

https://github.com/karlseguin/http.zig/blob/c8b04e3fef5abf32...