Add a very quick note about caching navs to the readme

Author: pattonwebz

README.md

@@ -115,6 +115,16 @@ add_filter( 'wp_nav_menu_args', 'prefix_modify_nav_menu_args' );
 ```
 Simply updating the walker may not be enough to get menus working right, you may need to add wrappers or additional classes, you can do that via the above function as well.
 
+### Menu Caching
+
+On some sites generating a large menu that rarely ever changes on every page request is an overhead that you may want to avoid. In those cases I can suggest you look at storing menu results in a transient.
+
+The biggest drawback to caching nav menus with this method is that it cannot easily apply the `.current-menu-item` or the `.active` class to the currently active item as WP decides what is currently active on page load - and since the menu is cached it only knows the active page that it was cached on originally.
+
+You can decide yourself if you want to put up with those drawbacks for the benefit of removing the menu generation time on most page loads. You can follow this article by Dave Clements to see how we cached nav menus that were generated by this walker: https://www.doitwithwp.com/use-transients-speed-wordpress-menus/
+
+Be sure to set the `echo` argument to FALSE in `the wp_nav_menu()` call when doing this so that the results can be stored instead of echoed to the page.
+
 ### Extras
 
 This script included the ability to use Bootstrap nav link mods in your menus through the WordPress menu UI. Disabled links, dropdown headers and dropdown dividers are supported. Additionally icon support is built-in for Glyphicons and Font Awesome (note: you will need to include the icon stylesheets or assets separately).
@@ -125,7 +135,7 @@ To add an Icon to your link simply enter Glypicons or Font Awesome class names i
 
 #### Icon-Only Items
 
-To make an item appear with the icon only apply the bootstrap screen reader class `sr-only` to the item alongside any icon classnames. This will then hide only the text that would appear as the link text. 
+To make an item appear with the icon only apply the bootstrap screen reader class `sr-only` to the item alongside any icon classnames. This will then hide only the text that would appear as the link text.
 
 #### Disabled Links