// noteUnusedDriverStatement notes that si is no longer used and should
// be closed whenever possible (when c is next not in use), unless c is
// already closed.
func (db *DB) noteUnusedDriverStatement(c *driverConn, si driver.Stmt) {
db.mu.Lock()
defer db.mu.Unlock()
if c.inUse {
c.onPut = append(c.onPut, func() {
si.Close()
})
} else {
c.Lock()
defer c.Unlock()
if !c.finalClosed {
si.Close()
}
}
}
