title: Akka pattern for instantiating an actor only if the entity it represents has previously been created?
body: <p>How can I only load an actor if it has previously been formally created following domain rules? Everything I've seen using <code>actorOf</code> and persistence always creates an empty instance and then applies the [possibly empty] set of events that have occurred, whereas I would prefer to make empty instances unrepresentable. Is there a standard approach for requiring a "created" event and otherwise triggering failure via "not found"?</p>
  
  <p>My thinking is to have one actor instance for each entity in the system, but my expectation is that less than 10% of the entities will be actively needed at any given time so I'm trying to avoid loading the entire set just to check validity when handling a request.</p>
  
  <p>I'm new to Akka and event sourcing in general so if I'm thinking about things from an unhelpful perspective I'm open to any alternatives as well.</p>