$gateway->router偶现取不到值的情况，导致服务异常退出

问题描述

$gateway->router偶现取不到值的情况，导致服务异常退出

程序代码

//指定 WebsocketBusinessWorker
        $gateway->router = function ($worker_connections, $client_connection) {
            $connection_names = [];
            foreach ($worker_connections as $key => $worker_connection) {
                $values = explode(':', $key);
                if ($values[1] == 'WebsocketBusinessWorker') {
                    $connection_names[$values[2]] = $key;
                }
            }
            if (!count($connection_names)) {
                return null;
            }
            $key = $connection_names[mt_rand(0, count($connection_names) - 1)];
            empty($client_connection->businessworker_address) && $client_connection->businessworker_address = $key;
            return $worker_connections[$client_connection->businessworker_address];
        };

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