/**
* Get the current volume of all the speakers in this group.
*
* @param Controller $controller The Controller to grab the state of
*
* @return static
*/
protected function getVolume(Controller $controller)
{
$this->speakers = [];
foreach ($controller->getSpeakers() as $speaker) {
$this->speakers[$speaker->getUuid()] = $speaker->getVolume();
}
return $this;
}