code: def _handle_field_value(self, field, value):
          
          if field == 'event':
              self._event = value
          elif field == 'data':
              self._data_lines.append(value)
          elif field == 'id':
              # Not implemented
              pass
          elif field == 'retry':
              # Not implemented
              pass
docs: Handle the field, value pair.