'Decrement the value, but do not update the channels QoS.
Note:
The MainThread will be responsible for calling :meth:`update`
when necessary.'

def decrement_eventually(self, n=1):

    with self._mutex:
        if self.value:
            self.value -= n
            if (self.value < 1):
                self.value = 1
    return self.value
