inmem_store.go
func (i *InmemStore) GetLog(index uint64, log *Log) error {
	i.l.RLock()
	defer i.l.RUnlock()
	l, ok := i.logs[index]
	if !ok {
		return ErrLogNotFound
	}
	*log = *l
	return nil
}
func (i *InmemStore) GetLog(index uint64, log *Log) error {
	i.l.RLock()
	defer i.l.RUnlock()
	l, ok := i.logs[index]
	if !ok {
		return ErrLogNotFound
	}
	*log = *l
	return nil
}
// GetLog implements the LogStore interface.