Major interference from Fast404

Just wanted to note here something I just encountered. Using ER with ER Autocomplete as a means of using fields to create references can be exceptionally slow when using Fast404.

I had to add this url fragment to my settings.php file to correct the issue:

$conf['fast_404_string_whitelisting'] = array('cdn/farfuture', '/advagg_', 'entityreference_autocomplete/autocomplete', 'entityreference/autocomplete' 'system/ajax');

Now instead of 30s to respond to the AJAX request, it takes 2 and actually returns values.