code: @JmxGetter(name = "lastSwapped", description = "Time in milliseconds since the store was swapped")
      public long getLastSwapped() {
          long timeSinceLastSwap = System.currentTimeMillis() - lastSwapped;
          return timeSinceLastSwap > 0 ? timeSinceLastSwap : 0;
      }
docs: Time since last time the store was swapped
  
  @return Time in milliseconds since the store was swapped