Unable to pause WASAPI output stream from callback

As the title says, I'm trying to pause a sound output stream from the callback.

The corresponding code is here: https://github.com/dingusdev/dingusppc/blob/ba81094fa278cfa3c59b9996f307e05c2109e845/devices/awacs.cpp#L179-L187

The above code works flawlessly with CoreAudio.

When running it with the WASAPI backend, `soundio_outstream_pause()` seems to have no effect. libsoundio continues to invoke the callback at infinitum.

The ability to pause a stream when data is exhausted is a requirement for us.

We're emulating a vintage sound DMA that should go idle when there is no more data. An operating system that runs in another thread polls the internal state of the DMA channel and blocks as long as the DMA channel is active.

Is there a possibility to make it work with WASAPI?