yii\mongodb\Collection::batchInsert PHP Method

    public function batchInsert($rows, $options = [])
    {
        $insertedIds = $this->database->createCommand()->batchInsert($this->name, $rows, $options);
        foreach ($rows as $key => $row) {
            $rows[$key]['_id'] = $insertedIds[$key];
        }
        return $rows;
    }