* eagerly fetches data for each source when iterated (rather than producing sources that only
   * load data through their streams). Prefer using the {@link #concat(Iterable)} overload if
   * possible.
   *
   * @param sources the sources to concatenate
   * @return a {@code CharSource} containing the concatenated data
   * @throws NullPointerException if any of {@code sources} is {@code null}

   * eagerly fetches data for each source when iterated (rather than producing sources that only
   * load data through their streams). Prefer using the {@link #concat(Iterable)} overload if
   * possible.
   *
   * @param sources the sources to concatenate
   * @return a {@code CharSource} containing the concatenated data
   * @throws NullPointerException if any of {@code sources} is {@code null}

   * @param unit the unit that {@code duration} is expressed in
   * @throws IllegalArgumentException if {@code duration} is not positive
   * @since 2.0
   */
  @SuppressWarnings("GoodTime") // Prefer the Duration overload
  public static <T extends @Nullable Object> Supplier<T> memoizeWithExpiration(
      Supplier<T> delegate, long duration, TimeUnit unit) {
    checkNotNull(delegate);

      return delegate;
    }

    @Override
    public int size() {
      return delegate.size() + delta;
    }
  }

  @SuppressWarnings("JoinIterableIterator") // explicitly testing iterator overload, too
  public void testNoSpecialNullBehavior() {
    checkNoOutput(J, iterable);
    checkResult(J, iterable1, "1");
    checkResult(J, iterable12, "1-2");
    checkResult(J, iterable123, "1-2-3");

    testBytes(numBytes, expectedCount, 0, -1);
  }

  /**
   * Helper to run the loop to test all the permutations for the number of bytes specified. This
   * overload is useful for debugging to get the loop to start at a certain character.
   *
   * @param numBytes the number of bytes in the byte array
   * @param expectedCount the expected number of roundtrippable permutations

   * @param unit the unit that {@code duration} is expressed in
   * @throws IllegalArgumentException if {@code duration} is not positive
   * @since 2.0
   */
  @SuppressWarnings("GoodTime") // Prefer the Duration overload
  public static <T extends @Nullable Object> Supplier<T> memoizeWithExpiration(
      Supplier<T> delegate, long duration, TimeUnit unit) {
    checkNotNull(delegate);

   *
   * <p><b>{@code Stream} equivalent:</b> {@link java.util.stream.Stream#of(Object[])
   * Stream.of(T...)}.
   *
   * @since 20.0 (since 18.0 as an overload of {@code of})
   */
  public static <E extends @Nullable Object> FluentIterable<E> from(E[] elements) {
    return from(Arrays.asList(elements));
  }

  /**

   *
   * <p><b>{@code Stream} equivalent:</b> {@link java.util.stream.Stream#of(Object[])
   * Stream.of(T...)}.
   *
   * @since 20.0 (since 18.0 as an overload of {@code of})
   */
  public static <E extends @Nullable Object> FluentIterable<E> from(E[] elements) {
    return from(Arrays.asList(elements));
  }

  /**

    // TODO: b/381289911 - Evaluate the performance impact of doing so.
    return join(parts.iterator());
  }

  /*
   * TODO: b/381289911 - Make the Iterator overload use StringJoiner (including Android or not)—or
   * some other optimization, given that StringJoiner can over-allocate:
   * https://bugs.openjdk.org/browse/JDK-8305774
   */

   * eagerly fetches data for each source when iterated (rather than producing sources that only
   * load data through their streams). Prefer using the {@link #concat(Iterable)} overload if
   * possible.
   *
   * @param sources the sources to concatenate
   * @return a {@code ByteSource} containing the concatenated data
   * @throws NullPointerException if any of {@code sources} is {@code null}