# File lib/bundler/fetcher.rb, line 51
      def user_agent
        @user_agent ||= begin
          ruby = Bundler.ruby_version

          agent = "bundler/#{Bundler::VERSION}"
          agent += " rubygems/#{Gem::VERSION}"
          agent += " ruby/#{ruby.version}"
          agent += " (#{ruby.host})"
          agent += " command/#{ARGV.first}"

          if ruby.engine != "ruby"
            # engine_version raises on unknown engines
            engine_version = ruby.engine_version rescue "???"
            agent += " #{ruby.engine}/#{engine_version}"
          end
          # add a random ID so we can consolidate runs server-side
          agent << " " << SecureRandom.hex(8)
        end
      end