<?php
class MqttConfig {
    private $configKeys = [
        'ali_mqtt_disjunctor',
    ];
    public function all() {
        $config = [];
        return [
                'disjunctor' => $config['ali_mqtt_disjunctor'] ?? 0,
        ];
    }
    public function username() {
        $config = $this->all();
        return 'Signature|' . $config['accessKey'] . '|' . $config['instanceId'];
    }
}