asFlowWithState

A Flow that emits a FlowMapStreamEvent to represent the state and its mutations over time.

On initial collection, it emits a single FlowMapStreamEvent.InitialState with the full initial map state. Later events are emitted as FlowMapStreamEvent.EventUpdate containing the Upsert or Removed deltas.

Note: This is the preferred method for performance-sensitive subscribers who need the current state immediately, as it avoids the overhead of processing individual events to reconstruct the initial map, while also avoiding the serialization cost of sending the full map on every subsequent update.