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

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

  }

  @AndroidIncompatible // Bug? expected:<1> but was:<2>
  public void testConcurrentExpirationLoading() throws InterruptedException {
    testConcurrentLoading(CacheBuilder.newBuilder().expireAfterWrite(10, SECONDS));
  }

  /**
   * On a successful concurrent computation, only one thread does the work, but all the threads get
   * the same result.
   */