The stream. One stream will be established per active entity. Once established, the first message sent will be Init, which contains the entity ID, and, if the entity has previously persisted a snapshot, it will contain that snapshot. It will then send zero to many event messages, one for each event previously persisted. The entity is expected to apply these to its state in a deterministic fashion. Once all the events are sent, one to many commands are sent, with new commands being sent as new requests for the entity come in. The entity is expected to reply to each command with exactly one reply message. The entity should reply in order, and any events that the entity requests to be persisted the entity should handle itself, applying them to its own state, as if they had arrived as events when the event stream was being replayed on load.