code: protected <T> T selfAs(final Class<T> protocol) {
      return lifeCycle.environment.stage.actorProxyFor(protocol, this, lifeCycle.environment.mailbox);
    }
docs: Answers this {@code Actor} as a {@code T} protocol. This {@code Actor} must implement the {@code Class<T>} protocol.
  @param protocol the {@code Class<T>} protocol
  @param <T> the protocol type
  @return T