Gatewayworker的多个Event如何使用全局变量？

class Events
{
    static $receiver = null;

    public static function onWorkerStart($businessWorker)
    {
        $reboot = Robot::getInstance();
    }

$inner_text_worker = new Worker('Text://0.0.0.0:5678');
$inner_text_worker->onMessage = function ($connection, $buffer) {
    Robot::getInstance()
};
$inner_text_worker->listen();

    protected function __construct()
    {
        echo "创建robot类\n";
    }

    public static function getInstance()
    {
        static $_instance = null;
        if ($_instance === null) {
            $_instance = new Robot();
        }
        return $_instance;
    }