/**
* Set metadata for all channels in the group
*
* @param string $group
* @param array|null $state
* @param string|null $uuid
*
* @throws PubnubException
*
* @return mixed|null
*/
public function setChannelGroupState($group, $state, $uuid = null)
{
if (empty($group)) {
throw new PubnubException('Missing Group in setChannelGroupState()');
}
$uuid = $uuid ? $uuid : $this->SESSION_UUID;
$state = PubnubUtil::url_encode(PubnubUtil::json_encode($state));
return $this->request(array('v2', 'presence', 'sub_key', $this->SUBSCRIBE_KEY, 'channel', '.', 'uuid', PubnubUtil::url_encode($uuid), 'data'), array('state' => $state, 'channel-group' => PubnubUtil::url_encode($group)));
}