code: protected void fireEvent(E event) {
  
      for (L listener : this.listeners) {
        try {
          fireEvent(event, listener);
        } catch (RuntimeException e) {
          handleListenerError(listener, event, e);
        }
      }
    }
docs: This method sends the given {@code event} to all {@link #addListener(EventListener) registered} listeners.
  
  @param event the event to set.