def flush(immediate=True):
    """ Flush any pending indexing actions for all indexes in this catalog.
        If ``immediate`` is ``True``, *all* actions will be immediately
        executed.  If ``immediate`` is ``False``,
        :attr:`~substanced.interfaces.MODE_DEFERRED` actions will be sent to
        the actions processor if one is active, and all other actions will be
        executed immediately."""
