HasError returns true if is not a empty error.

Retryable return true meas a retryable error.

Error is a raft error.

KeyNotInShard the key is not found on the store.

NotLeader the current shard peer is not leader.

RaftEntryTooLarge raft entry is too large.

ServerIsBusy the server is busy.

ShardNotFound the shard replica is not found on the store.

ShardUnavailable the shard is unavailable, maybe destoryed.

StaleCommand the command is stale, need to retry.

StaleEpoch the current shard peer is stale.

StoreNotMatch current store is not match.