audioBitrateProfile

The audio bitrate profile currently in force — observe this to drive a music/voice toggle.

Only moves when the profile actually took. Set before joining it always does, since the pipeline is then built from it. On a running call it moves only if every reachable stage accepted the change; otherwise it keeps reporting the previous profile, so a toggle bound to it snaps back rather than claiming a switch the audio did not make, and setAudioBitrateProfile fails naming the stages that refused.