code: private void displayCrouton() {
      if (croutonQueue.isEmpty()) {
        return;
      }
  
      // First peek whether the Crouton has an activity.
      final Crouton currentCrouton = croutonQueue.peek();
  
      // If the activity is null we poll the Crouton off the queue.
      if (null == currentCrouton.getActivity()) {
        croutonQueue.poll();
      }
  
      if (!currentCrouton.isShowing()) {
        // Display the Crouton
        sendMessage(currentCrouton, Messages.ADD_CROUTON_TO_VIEW);
        if (null != currentCrouton.getLifecycleCallback()) {
          currentCrouton.getLifecycleCallback().onDisplayed();
        }
      } else {
        sendMessageDelayed(currentCrouton, Messages.DISPLAY_CROUTON, calculateCroutonDuration(currentCrouton));
      }
    }
docs: Displays the next {@link Crouton} within the queue.