public function handleNick(
        \Erebot\Interfaces\EventHandler $handler,
        \Erebot\Interfaces\Event\Nick   $event
    ) {
        $oldNick    = (string) $event->getSource();
        $newNick    = (string) $event->getTarget();

        $collator       = $this->connection->getCollator();
        $normOldNick    = $collator->normalizeNick($oldNick);
        $normNewNick    = $collator->normalizeNick($newNick);
        $key = array_search($normOldNick, $this->nicks);
        if ($key === false) {
            return;
        }

        $this->realRemoveUser($normNewNick);
        $this->nicks[$key]         = $normNewNick;
        $this->ial[$key]['nick']   = $newNick;
    }