public function poll($idSite, $visitorId = false, $microtime = false, $fromAdmin = false)
{
if ($fromAdmin) {
$this->authenticate($idSite);
$fromAdmin = Piwik::getCurrentUserLogin();
} else {
header("Access-Control-Allow-Origin: *");
}
$conversation = new ChatConversation($idSite, $visitorId);
return $conversation->poll($microtime, $fromAdmin);
}