docs: public synchronized void update(double sample) {
          long now = System.currentTimeMillis();
  
          if (lastMillis == 0) {    // first sample
              average = sample;
              lastMillis = now;
              return;
          }
          long deltaTime = now - lastMillis;
          double coeff = Math.exp(-1.0 * ((double)deltaTime / windowMillis));
          average = (1.0 - coeff) * sample + coeff * average;
  
          lastMillis = now;
      }