code: func (h *healthcheckManager) expire() {
  	h.lock.RLock()
  	ids := h.ids
  	h.lock.RUnlock()
  
  	status := healthcheck.Status{State: healthcheck.StateUnknown}
  	for _, id := range ids {
  		h.queueHealthState(&healthcheck.Notification{id, status})
  	}
  }
docs: // expire invalidates the state of all configured healthchecks.