public static function configure()
    {
        static $configured = false;
        if (!$configured) {
            register_shutdown_function(array('Aoe_Scheduler_Helper_GracefulDead', 'beforeDyingShutdown'));
            if (extension_loaded('pcntl') && function_exists('pcntl_signal')) {
                declare(ticks = 1);
                pcntl_signal(SIGINT, array('Aoe_Scheduler_Helper_GracefulDead', 'beforeDyingSigint')); // CTRL + C
                pcntl_signal(SIGTERM, array('Aoe_Scheduler_Helper_GracefulDead', 'beforeDyingSigterm')); // kill <pid>
            }
            $configured = true;
        }
    }