Question on sndio 1.8.1: SIO_PLAY and SIO_REC

Hi all,

I was tinkering with sndio on a fresh OpenBSD 7.1 install and tried to use
the synchronous mode by using a simple application that opens a handle
(sio_open()) with both SIO_PLAY and SIO_REC modes set (mode = SIO_PLAY |
SIO_REC).

From the documentation: it should now be possible to record from the
microphone and get this recording immediately output through my
speakers, pseudo-simultaneously.

Problem is, it does not work. The symptoms are: it freezes at sio_psleep()
and nothing happens.

The same setup (OS, microphone, speakers) works correctly when used in
either SIO_PLAY or SIO_REC mode. I have also tried to record first and then
playback the recorded data (using two sio_open(), sio_start(),
sio_read/write(), ... sio_stop(), sio_close() sequences) in the same
program. Works flawlessly.

What am I doing wrong?

Regards