* @throws IllegalStateException if {@link #expireAfterAccess} was already set
   */
  @SuppressWarnings("GoodTime") // should accept a Duration
  @CanIgnoreReturnValue
  public CacheBuilder<K, V> expireAfterAccess(long duration, TimeUnit unit) {
    checkState(
        expireAfterAccessNanos == UNSET_INT,
        "expireAfterAccess was already set to %s ns",
        expireAfterAccessNanos);