maintenance/maintenance.go
func (s *FileStore) Off() (changed bool, err error) {
	_, err = os.Stat(s.filename)
	if os.IsNotExist(err) {
		err = nil
		return
	}
	if err != nil {
		return
	}
	if err = os.Remove(s.filename); err != nil {
		return
	}
	changed = true
	return
}
func (s *FileStore) Off() (changed bool, err error) {
	_, err = os.Stat(s.filename)
	if os.IsNotExist(err) {
		err = nil
		return
	}
	if err != nil {
		return
	}
	if err = os.Remove(s.filename); err != nil {
		return
	}
	changed = true
	return
}
// Off disables maintenance.