Well, HN is written in Arc, which is a layer on top of MzScheme. MzScheme handling of sockets is actually already done with the select() syscall, and its "thre

Well, HN is written in Arc, which is a layer on top of MzScheme. MzScheme handling of sockets is actually already done with the select() syscall, and its "threads" are lightweight non-blocking threads (think Erlang). So it's already async but with "sugar".