This alsa plugin provides a pcm that connects to a sndiod server as a fallback for applications that don't support sndio.
At the moment only playback is supported, capturing might be added later.
Each time the pcm is used a new sndio slot is created and sndio can control the volume per application.
The downside of this fallback instead of using sndio directly is that the application can't have control over the sndio per slot volume because alsa has no "per application" mixers.
The simplest .asoundrc just sets the default pcm to this plugin.
pcm.!default {
type sndio
}
The volume configuration option can be used to set an initial volume.
The device is used to overwrite the default device and/or the device
set by the AUDIODEVICE environment variable.