/**
  * Rebuilds the (ECP) custom/additional field data for the specified event.
  *
  * This ensures that events last created/updated under ECP 3.12.x or earlier with
  * "multichoice"-type  additional fields have all the expected entries in the post
  * meta table.
  *
  * @param $event_id
  */
 public function rebuild_fields($event_id)
 {
     $fields = array();
     foreach ((array) tribe_get_option('custom-fields', array()) as $custom_field) {
         $value = get_post_meta($event_id, $custom_field['name'], true);
         // If this is a multichoice field, break it down from a pipe-separated format to an array
         if (Tribe__Events__Pro__Custom_Meta::is_multichoice($custom_field)) {
             $value = explode('|', $value);
         }
         $fields[$custom_field['name']] = $value;
     }
     // Trigger an update
     Tribe__Events__Pro__Custom_Meta::save_single_event_meta($event_id, $fields);
 }