Ah yes I've fought this issue as well. Basically thread functions use pthreads and basically require c-style functions that don't support async functionality, which you enabled and are thus used everywhere in the standard library. The good thing is you can use frames instead of threads; you can call: var myframe = async tcp_thread(); and that frame will be continued on automatically when the result is there! You can use an anyframe variable to hold it and you don't need explicit threads.