func (b *RefCountBox) Free() {
	b.Lock()
	defer b.Unlock()

	b.count--
	if b.count == 0 {
		b.db.Close()
		b.db = DB{}
	}
}
func (b *RefCountBox) Free() {
	b.Lock()
	defer b.Unlock()

	b.count--
	if b.count == 0 {
		b.db.Close()
		b.db = DB{}
	}
}
func ( b * RefCountBox ) Free ( ) { b . Lock ( ) defer b . Unlock ( ) b . count -- if b . count == 0 { b . db . Close ( ) b . db = DB { } } }
// Free decreases the reference count. It close the DB if the count reaches
// zero.
Free decreases the reference count . It close the DB if the count reaches zero .