* or {@code loadExceptionCount} is incremented.
   */
  @SuppressWarnings("GoodTime") // should return a java.time.Duration
  public long totalLoadTime() {
    return totalLoadTime;
  }

  /**
   * Returns the average time spent loading new values. This is defined as {@code totalLoadTime /
   * (loadSuccessCount + loadExceptionCount)}.
   *