docs: def wait(self, until=0):
          """wait until the count has reached a particular number
  
          .. note:: this method can block the current greenlet
  
          :param until:
              the number to wait for the count to get down (or up) to. default 0
          :type until: int
          """
          if self._count != until:
              self._waiters.setdefault(until, []).append(compat.getcurrent())
              scheduler.state.mainloop.switch()