The same as muted.
Whether output is muted; volume 0 counts as muted.
Always true here; a failed call resolves with ApiFailure instead.
Volume as a percentage from 0 to 100, converted from the decibel value; 0 when muted.
Volume in decibels, -100 (silence) to 0 (full).
Successful response from
playback.getVolume.