title: Akka Cluster Sharding Entity query
body: <p>I am working on changing a single node akka actor system application to be akka cluster. One change is making a type of stateful Actor (which can be many at runtime), into Cluster Sharding managed entities. Now it works fine on multiple nodes. </p>
  
  <p>One problem I am facing is how to query (GET ALL) the entities created by Sharding Regions in Cluster. Previously in single node mode, it uses actor system ActorSelection to do actor path matching to get a list of matched actors, which does not work any longer in cluster sharding. </p>
  
  <p>I would like to know if Sharding Region has some built-in support for querying its entities.</p>