This action hook will run just after the trail population check, and before attempting to fill bcn_breadcrumb_trail::trail. It is located in bcn_breadcrumb_trail::fill(). It receives one parameter:
&$breadcrumb_trail – (bcn_breadcrumb_trail)(required) A reference to the current bcn_breadcrumb_trail instance.
Note: Do not exit with a cleared bcn_breadcrumb_trail::trail, otherwise an inescapable loop may result.