docs: def send_response(self, body, set_content_type=True):
          """
          Serialize and send ``body`` in the response.
  
          :param dict body: the body to serialize
          :param bool set_content_type: should the :http:header:`Content-Type`
              header be set?  Defaults to :data:`True`
  
          """
          settings = get_settings(self.application, force_instance=True)
          handler = settings[self.get_response_content_type()]
          content_type, data_bytes = handler.to_bytes(body)
          if set_content_type:
              self.set_header('Content-Type', content_type)
              self.add_header('Vary', 'Accept')
          self.write(data_bytes)