    # File lib/action_mailer/vendor/tmail-1.2.3/tmail/mailbox.rb, line 105
        def each_new_port( mtime = nil, &block )
          mtime ||= @last_atime
          return each_port(&block) unless mtime
          return unless File.mtime(@dirname) >= mtime

          mail_files().each do |path|
            yield PORT_CLASS.new(path) if File.mtime(path) > mtime
          end
          @last_atime = Time.now
        end