public static function getInstance($seconds = 15)
{
if (empty(self::$instance)) {
$class = __CLASS__;
self::$instance = new $class($seconds);
}
return self::$instance;
}
/**
* Provided only for tests that want to kill object in tearDown()
*/
public static function destroyInstance() {
if (isset(self::$instance)) {
self::$instance = null;
}
}