variant

# File actionpack/lib/action_controller/metal/mime_responds.rb, line 312
        def variant
          if @variant.nil?
            @variants[:none] || @variants[:any]
          elsif (@variants.keys & @variant).any?
            @variant.each do |v|
              return @variants[v] if @variants.key?(v)
            end
          else
            @variants[:any]
          end
        end