code: def send_response_only(self, code, message=None):
          
          if message is None:
              if code in self.responses:
                  message = self.responses[code][0]
              else:
                  message = ''
          if self.request_version != 'HTTP/0.9':
              if not hasattr(self, '_headers_buffer'):
                  self._headers_buffer = []
              self._headers_buffer.append(("%s %d %s\r\n" %
                      (self.protocol_version, code, message)).encode(
                          'latin-1', 'strict'))
docs: Send the response header only.