response

# File actionpack/lib/action_controller/metal/mime_responds.rb, line 272
      def response
        response = @responses.fetch(format, @responses[Mime::ALL])
        if response.is_a?(VariantCollector) # `format.html.phone` - variant inline syntax
          response.variant
        elsif response.nil? || response.arity == 0 # `format.html` - just a format, call its block
          response
        else # `format.html{ |variant| variant.phone }` - variant block syntax
          variant_collector = VariantCollector.new(@variant)
          response.call(variant_collector) # call format block with variants collector
          variant_collector.variant
        end
      end