code: protected CompletableFuture<?> ask(Object message, Time timeout) {
  		return FutureUtils.toJava(
  			Patterns.ask(rpcEndpoint, message, timeout.toMilliseconds()));
  	}
docs: Sends the message to the RPC endpoint and returns a future containing
  its response.
  
  @param message to send to the RPC endpoint
  @param timeout time to wait until the response future is failed with a {@link TimeoutException}
  @return Response future