def encode(response)
      [200,
       { Rack::CONTENT_TYPE => 'text/html',
         Rack::CONTENT_LENGTH => response.size.to_s },
       [response]]
    end
def encode(response)
      [200,
       { Rack::CONTENT_TYPE => 'text/html',
         Rack::CONTENT_LENGTH => response.size.to_s },
       [response]]
    end
Response with text/html response.
 @param response [String] response from format handler block.
 @return Rack response {Array}