.expireAfterAccess(1, NANOSECONDS)
            .build(identityLoader());
    // 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 // Duration