ref: ec5f2d23637dadf6d2893bf6f2f829b070ec3b34
dir: /lib/thread/spawn+plan9.myr/
use std use sys pkg thread = type tid = uint64 const spawn : (fn : (-> void) -> std.result(tid, byte[:])) ;; const spawn = {fn match sys.rfork(sys.Rfproc | sys.Rfmem | sys.Rfnowait) | 0: fn() std.exit(0) | -1: -> `std.Fail "unable to spawn thread" | thr: -> `std.Ok (thr : tid) ;; }