func (ms *MemoryStorage) LastIndex() (uint64, error) {
	ms.Lock()
	defer ms.Unlock()
	return ms.lastIndex(), nil
}
func (ms *MemoryStorage) LastIndex() (uint64, error) {
	ms.Lock()
	defer ms.Unlock()
	return ms.lastIndex(), nil
}
func ( ms * MemoryStorage ) LastIndex ( ) ( uint64 , error ) { ms . Lock ( ) defer ms . Unlock ( ) return ms . lastIndex ( ) , nil }
// LastIndex implements the Storage interface.
LastIndex implements the Storage interface .