I think it's reasonable to ask for clarity on this point. One might, reasonably imo, expect buffering. (And E2BIG if a size limit is exceeded.) You have to dive

I think it's reasonable to ask for clarity on this point. One might, reasonably imo, expect buffering. (And E2BIG if a size limit is exceeded.) You have to dive deeper into the spec than a genre savvy user should need to learn this.