raft/storage.go
func (ms *MemoryStorage) FirstIndex() (uint64, error) {
	ms.Lock()
	defer ms.Unlock()
	return ms.firstIndex(), nil
}
func (ms *MemoryStorage) FirstIndex() (uint64, error) {
	ms.Lock()
	defer ms.Unlock()
	return ms.firstIndex(), nil
}
func ( ms * MemoryStorage ) FirstIndex ( ) ( uint64 , error ) { ms . Lock ( ) defer ms . Unlock ( ) return ms . firstIndex ( ) , nil }
// FirstIndex implements the Storage interface.
FirstIndex implements the Storage interface .