message AppendEntriesRequest {
  required string group_id = 1;
  required string server_id = 2;
  required string peer_id = 3;
  required int64 term = 4;
  required int64 prev_log_term = 5;
  required int64 prev_log_index = 6;
  repeated .braft.EntryMeta entries = 7;
  required int64 committed_index = 8;
}