protected function verboseTimer($callback, $always = false)
    {
        $took = microtime(true) - $this->start;
        if (($always || $took > 1) && $this->output->isVeryVerbose()) {
            $message = $callback($took);
            $this->output->writeln($message);
        }
        $this->start = microtime(true);
    }