def __die(self, synchronous=False):
        """Closes this cursor.
        """
        already_killed = self.__killed
        self.__killed = True
        if self.__id and not already_killed:
            address = _CursorAddress(
                self.__address, self.__collection.full_name)
            if synchronous:
                self.__collection.database.client._close_cursor_now(
                    self.__id, address, session=self.__session)
            else:
                # The cursor will be closed later in a different session.
                self.__collection.database.client._close_cursor(
                    self.__id, address)
        self.__end_session(synchronous)
Closes this cursor.