store/mongo.go
func (ms *MongoStore) Write(words ...string) error {
	if len(words) == 0 {
		return nil
	}

	var err error
	ms.c(func(c *mgo.Collection) {
		for i, l := 0, len(words); i < l; i++ {
			_, err = c.Upsert(_Dirties{Value: words[i]}, _Dirties{Value: words[i]})
		}
	})
	if err != nil {
		return err
	}

	atomic.AddUint64(&ms.version, 1)
	return nil
}
func (ms *MongoStore) Write(words ...string) error {
	if len(words) == 0 {
		return nil
	}

	var err error
	ms.c(func(c *mgo.Collection) {
		for i, l := 0, len(words); i < l; i++ {
			_, err = c.Upsert(_Dirties{Value: words[i]}, _Dirties{Value: words[i]})
		}
	})
	if err != nil {
		return err
	}

	atomic.AddUint64(&ms.version, 1)
	return nil
}
// Write Write