Does Plan 9 have an equivalent to alsa or jackaudio or pipewire, where you can pick a (usually shared memory) ring buffer size, have the kernel or daemon alert you (usually through a poll fd) when there's room in the buffer, and only then perform the necessary calculations (instead of performing a blocking write which adds latency)? What about synchronously receiving blocks of input audio as soon as available, and outputting equally-sized aligned blocks of output audio played back exactly two periods of buffering after the matching input audio? Or chaining three or more apps in a pipeline, all woken in sequence whenever input data is available, and still have only two periods of latency?