docs: public synchronized void tick() {
          long currentTime = GVRTime.getMilliTime();
          long cutoffTime = currentTime - BUFFER_SECONDS * 1000;
          ListIterator<Long> it = mTimestamps.listIterator();
          while (it.hasNext()) {
              Long timestamp = it.next();
              if (timestamp < cutoffTime) {
                  it.remove();
              } else {
                  break;
              }
          }
  
          mTimestamps.add(currentTime);
          mStatColumn.addValue(((float)mTimestamps.size()) / BUFFER_SECONDS);
      }