public function setConfig($config = array())
    {
        if ($config instanceof Zend_Config) {
            $config = $config->toArray();

        } elseif (! is_array($config)) {

            throw new Zend_Http_Client_Adapter_Exception(
                'Array or Zend_Config object expected, got ' . gettype($config)
            );
        }

        foreach ($config as $k => $v) {
            $this->config[strtolower($k)] = $v;
        }
    }