code: @Controller(events = {EventType.MESSAGE, EventType.POSTBACK}, pattern = "^(?i)(hi|hello|hey)$")
      public void onGetStarted(Event event) {
          // quick reply buttons
          Button[] quickReplies = new Button[]{
                  new Button().setContentType("text").setTitle("Sure").setPayload("yes"),
                  new Button().setContentType("text").setTitle("Nope").setPayload("no")
          };
          reply(event, new Message().setText("Hello, I am JBot. Would you like to see more?").setQuickReplies(quickReplies));
      }
docs: This method gets invoked when a user clicks on the "Get Started" button or just when someone simply types
  hi, hello or hey. When it is the former, the event type is {@code EventType.POSTBACK} with the payload "hi"
  and when latter, the event type is {@code EventType.MESSAGE}.
  
  @param event