wpdb::__destruct PHP Method

    public function __destruct()
    {
        return true;
    }

 function do_pings()
 {
     global $wpdb, $vaultpress_pings, $__vp_recursive_ping_lock;
     if (defined('WP_IMPORTING') && constant('WP_IMPORTING')) {
         return;
     }
     if (!isset($wpdb)) {
         $wpdb = new wpdb(DB_USER, DB_PASSWORD, DB_NAME, DB_HOST);
         $close_wpdb = true;
     } else {
         $close_wpdb = false;
     }
     if (!$vaultpress_pings['count']) {
         return;
     }
     // Short circuit the contact process if we know that we can't contact the service
     if (isset($__vp_recursive_ping_lock) && $__vp_recursive_ping_lock) {
         $this->ai_ping_insert(serialize($vaultpress_pings));
         if ($close_wpdb) {
             $wpdb->__destruct();
             unset($wpdb);
         }
         $this->reset_pings();
         return;
     }
     $ping_attempts = 0;
     do {
         $ping_attempts++;
         $rval = $this->contact_service('ping', array('args' => $vaultpress_pings));
         if ($rval || $ping_attempts >= 3) {
             break;
         }
         if (!$rval) {
             usleep(500000);
         }
     } while (true);
     if (!$rval) {
         $__vp_recursive_ping_lock = true;
         $this->ai_ping_insert(serialize($vaultpress_pings));
     }
     $this->reset_pings();
     if ($close_wpdb) {
         $wpdb->__destruct();
         unset($wpdb);
     }
     return $rval;
 }