*   <li>{@code expireAfterAccess=[duration]}: sets {@link CacheBuilder#expireAfterAccess}.
 *   <li>{@code expireAfterWrite=[duration]}: sets {@link CacheBuilder#expireAfterWrite}.
 *   <li>{@code refreshAfterWrite=[duration]}: sets {@link CacheBuilder#refreshAfterWrite}.
 *   <li>{@code weakKeys}: sets {@link CacheBuilder#weakKeys}.
 *   <li>{@code softValues}: sets {@link CacheBuilder#softValues}.
 *   <li>{@code weakValues}: sets {@link CacheBuilder#weakValues}.

        IllegalArgumentException.class, () -> builder.refreshAfterWrite(java.time.Duration.ZERO));
  }

  @GwtIncompatible // refreshAfterWrite
  public void testRefresh_setTwice() {
    CacheBuilder<Object, Object> builder =
        CacheBuilder.newBuilder().refreshAfterWrite(3600, SECONDS);
    assertThrows(IllegalStateException.class, () -> builder.refreshAfterWrite(3600, SECONDS));
  }

 *   <li>{@code expireAfterAccess=[duration]}: sets {@link CacheBuilder#expireAfterAccess}.
 *   <li>{@code expireAfterWrite=[duration]}: sets {@link CacheBuilder#expireAfterWrite}.
 *   <li>{@code refreshAfterWrite=[duration]}: sets {@link CacheBuilder#refreshAfterWrite}.
 *   <li>{@code weakKeys}: sets {@link CacheBuilder#weakKeys}.
 *   <li>{@code softValues}: sets {@link CacheBuilder#softValues}.
 *   <li>{@code weakValues}: sets {@link CacheBuilder#weakValues}.

    // well, it didn't blow up.
  }

  @GwtIncompatible // refreshAfterWrite
  public void testRefresh_zero() {
    CacheBuilder<Object, Object> builder = CacheBuilder.newBuilder();
    assertThrows(IllegalArgumentException.class, () -> builder.refreshAfterWrite(0, SECONDS));
  }

  @GwtIncompatible // refreshAfterWrite
  public void testRefresh_setTwice() {
    CacheBuilder<Object, Object> builder =

   * @throws IllegalStateException if {@link #refreshAfterWrite} was already set
   * @since 11.0
   */
  @GwtIncompatible // To be supported (synchronously).
  @SuppressWarnings("GoodTime") // should accept a java.time.Duration
  @CanIgnoreReturnValue
  public CacheBuilder<K, V> refreshAfterWrite(long duration, TimeUnit unit) {
    checkNotNull(unit);