# File lib/chromedriver/helper.rb, line 19
    def download(hit_network = false)
      return if File.exist?(binary_path) && !hit_network

      raise "Version not found for #{download_version}" unless download_url

      filename = File.basename download_url
      Dir.chdir platform_install_dir do
        FileUtils.rm_f filename
        File.open(filename, "wb") do |saved_file|
          URI.parse(download_url).open("rb") do |read_file|
            saved_file.write(read_file.read)
          end
        end

        raise "Could not download #{download_url}" unless File.exists? filename
        Archive::Zip.extract(filename, '.', :overwrite => :all)
      end
      raise "Could not unzip #{filename} to get #{binary_path}" unless File.exists? binary_path
      FileUtils.chmod "ugo+rx", binary_path
      File.open(version_path, 'w') { |file| file.write(download_version) }
    end