    # File lib/action_mailer/vendor/tmail-1.2.3/tmail/mail.rb, line 340
        def ordered_each
          list = @header.keys
          FIELD_ORDER.each do |name|
            if list.delete(name)
              [@header[name]].flatten.each {|v| yield name, v }
            end
          end
          list.each do |name|
            [@header[name]].flatten.each {|v| yield name, v }
          end
        end