public function __construct($config = [])
 {
     if (isset($config['bulk_base_uri'])) {
         $base_uri = $config['bulk_base_uri'];
     } else {
         $base_uri = 'https://' . SalesforceConfig::get('salesforce.api.domain');
     }
     $client_config = ['base_uri' => $base_uri, 'auth' => 'bulk'];
     if (isset($config['handler'])) {
         $client_config['handler'] = $config['handler'];
     }
     $this->oauth2Client = new BulkClient($client_config);
     parent::__construct(array_replace($config, $client_config));
 }