protected function registerClient()
    {
        $this->app->singleton('api.client', function ($app) {
            $client = new Client(
                $app['encrypter'],
                $app['config']->get('api.clients', [])
            );

            $client->setDefaultAppKey($app['config']->get('api.default_client'));

            return $client;
        });

        $this->app->alias('api.client', Client::class);
    }