docs: def tick(self):
          """Decay the current rate according to the elapsed time"""
  
          instant_rate = float(self.value) / float(self.tick_interval)
  
          with self.lock:
              if self.initialized:
                  self.rate += (self.alpha * (instant_rate - self.rate))
              else:
                  self.initialized = True
                  self.rate = instant_rate
  
              self.value = 0