Request to load all entries. It must reply with 0 or more `LoadData` messages followed by one `LoadAllCompleted` message to the `sender` (the `Replicator`). If the `LoadAll` fails it can throw `LoadFailedException` and the `Replicator` supervisor will stop itself and the durable store.

Request to store an entry. It optionally contains a StoreReply, which should be used to signal success or failure of the operation to the contained ReplyTo actor.