# 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')
          body = []
        end
        [status, headers, body]
      else
        @app.call(env)
      end
    end