def METHOD_NAME(self, fragment: Fragment) -> None:
    payload = self._assume_binary(fragment)
    if self._buf_header is None:
        raise ValidationError("Consuming a buffer payload, but current buffer header is None")
    header = BufferHeader(id=self._buf_header["id"])
    cast(Message[Any], self._partial).assemble_buffer(header, payload)
    self._check_complete()