WriteVector
getset
[Orleans.Id(1)]public string WriteVector Metadata that is used to avoid duplicate appends. Logically, this is a (string->bit) map, the keys being replica ids But this map is represented compactly as a simple string to reduce serialization/deserialization overhead Bits are read by
Orleans.EventSourcing.LogStorage.LogStateWithMetaData.GetBit and flipped by Orleans.EventSourcing.LogStorage.LogStateWithMetaData.FlipBit. Bits are toggled when writing, so that the retry logic can avoid appending an entry twice when retrying a failed append. 