# File lib/bundler/rubygems_integration.rb, line 595
      def download_gem(spec, uri, path)
        uri = Bundler.settings.mirror_for(uri)
        fetcher = gem_remote_fetcher
        fetcher.headers = { "X-Gemfile-Source" => spec.remote.original_uri.to_s } if spec.remote.original_uri
        fetcher.download(spec, uri, path)
      end