# File lib/rack/conditionalget.rb, line 22
    def call(env)
      case env[REQUEST_METHOD]
      when "GET", "HEAD"
        status, headers, body = @app.call(env)
        headers = Utils::HeaderHash.new(headers)
        if status == 200 && fresh?(env, headers)
          status = 304
          headers.delete(CONTENT_TYPE)
          headers.delete(CONTENT_LENGTH)
          original_body = body
          body = Rack::BodyProxy.new([]) do
            original_body.close if original_body.respond_to?(:close)
          end
        end
        [status, headers, body]
      else
        @app.call(env)
      end
    end