'Flush any pending deallocations unless it is disabled.
Do nothing if disabled.'

def clear(self):

    if (not self.is_disabled):
        while self._cons:
            [dtor, handle, size] = self._cons.popleft()
            _logger.info('dealloc:    %s    %s    bytes', dtor.__name__, size)
            dtor(handle)
        self._size = 0
