'A wrapper around the \'real\' record hook, the _hook method, which
prevents recursion. This isn\'t making any effort to be threadsafe,
the intent is to outright block infinite recursion via a
job.record->_hook->job.record->_hook->job.record... chain.'

def __call__(self, entry):

    if self._being_called:
        return
    self._being_called = True
    try:
        self._hook(self._job, entry)
    finally:
        self._being_called = False
