code: def include_in_user_agent(name, suffix = nil)
        return if name.nil?
        unless @config.read('library.include_utilities_in_user_agent') == false
          @extra_user_agents_lock.synchronize do
            @extra_user_agents[name] = suffix
          end
        end
      end
docs: Adds a custom string to the user agent, one time, the next time a user
   agent is generated. This will be rendered in the format "name/suffix",
   or just "name" if the suffix is nil or omitted.