UserService.java

public class UserService {
  
  private Duration askTimeout;
  
  public CompletionStage<Result> create(CreateUser createUser) {
    getUserEntityRef(createUser.userId()).ask(replyTo -> UserCommandEnvelope.of(createUser, replyTo), askTimeout);
  }
  
  public CompletionStage<Result> verify(VerifyUser verifyUser) {
    getUserEntityRef(verifyUser.userId()).ask(replyTo -> UserCommandEnvelope.of(verifyUser, replyTo), askTimeout);
  }
  
  private EntityRef<UserEntity> getUserEntityRef(String userId) {
    return ...; //depends on deployment strategy local vs cluster
  }
}