public function start()
    {
        if (!isset($this->config['walkers']) || empty($this->config['walkers'])) {
            $this->logger->log(LibLog::LOG_ERROR, "There is not an available walker configured.");
            return false;
        }
        foreach ($this->config['walkers'] as $walker_name => $status) {
            if ($status) {
                $goNext=$this->walkWith($walker_name);
                if (!$goNext) {
                    $this->logger->log(LibLog::LOG_WARNING, "The walker '{$walker_name}' stopped walking, exit.");
                    return false;
                }
            }
        }
        $this->logger->log(LibLog::LOG_INFO, "All walkers have satisfied.");
        return true;
    }