code: public final void initActor(UUID uuid, String path, ActorContext context, Mailbox mailbox) {
          this.uuid = uuid;
          this.path = path;
          this.context = context;
          this.mailbox = mailbox;
          this.askPattern = new ActorAskImpl(self());
          this.typedAsk = new TypedAskExtensions(self());
          this.callbackExtension = new CallbackExtension(self());
          this.extensions.add(askPattern);
          this.extensions.add(typedAsk);
          this.extensions.add(callbackExtension);
          this.extensions.add(new RunnableExtension());
      }
docs: <p>INTERNAL API</p>
  Initialization of actor
  
  @param uuid    uuid of actor
  @param path    path of actor
  @param context context of actor
  @param mailbox mailbox of actor