* #toMap(Iterable, Function)}.
   *
   * <p>Specifically, for each {@code k} in the backing set, the returned map has an entry mapping
   * {@code k} to {@code function.apply(k)}. The {@code keySet}, {@code values}, and {@code
   * entrySet} views of the returned map iterate in the same order as the backing set.
   *
   * <p>Modifications to the backing set are read through to the returned map. The returned map

   * #toMap(Iterable, Function)}.
   *
   * <p>Specifically, for each {@code k} in the backing set, the returned map has an entry mapping
   * {@code k} to {@code function.apply(k)}. The {@code keySet}, {@code values}, and {@code
   * entrySet} views of the returned map iterate in the same order as the backing set.
   *
   * <p>Modifications to the backing set are read through to the returned map. The returned map

    @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 0;
  }

  /**
   * Returns a supplier whose {@code get()} method synchronizes on {@code delegate} before calling
   * it, making it thread-safe.
   */
  @J2ktIncompatible
  public static <T extends @Nullable Object> Supplier<T> synchronizedSupplier(
      Supplier<T> delegate) {
    return new ThreadSafeSupplier<>(delegate);
  }

    @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 0;
  }

  /**
   * Returns a supplier whose {@code get()} method synchronizes on {@code delegate} before calling
   * it, making it thread-safe.
   */
  @J2ktIncompatible
  public static <T extends @Nullable Object> Supplier<T> synchronizedSupplier(
      Supplier<T> delegate) {
    return new ThreadSafeSupplier<>(delegate);
  }

            durationInNanos(refreshDuration, refreshTimeUnit),
            durationInNanos(that.refreshDuration, that.refreshTimeUnit));
  }

  /**
   * Converts an expiration duration/unit pair into a single Long for hashing and equality. Uses
   * nanos to match CacheBuilder implementation.
   */
  private static @Nullable Long durationInNanos(long duration, @Nullable TimeUnit unit) {
    return (unit == null) ? null : unit.toNanos(duration);

            durationInNanos(refreshDuration, refreshTimeUnit),
            durationInNanos(that.refreshDuration, that.refreshTimeUnit));
  }

  /**
   * Converts an expiration duration/unit pair into a single Long for hashing and equality. Uses
   * nanos to match CacheBuilder implementation.
   */
  private static @Nullable Long durationInNanos(long duration, @Nullable TimeUnit unit) {
    return (unit == null) ? null : unit.toNanos(duration);

      public Iterator<T> iterator() {
        return Iterators.concat(Iterators.transform(inputs.iterator(), Iterable::iterator));
      }
    };
  }

  /** Concatenates a varargs array of iterables without making a defensive copy of the array. */
  private static <T extends @Nullable Object> FluentIterable<T> concatNoDefensiveCopy(
      Iterable<? extends T>... inputs) {
    for (Iterable<? extends T> input : inputs) {

      public Iterator<T> iterator() {
        return Iterators.concat(Iterators.transform(inputs.iterator(), Iterable::iterator));
      }
    };
  }

  /** Concatenates a varargs array of iterables without making a defensive copy of the array. */
  private static <T extends @Nullable Object> FluentIterable<T> concatNoDefensiveCopy(
      Iterable<? extends T>... inputs) {
    for (Iterable<? extends T> input : inputs) {

   * @param h hash code
   */
  static int rehash(int h) {
    // Spread bits to regularize both segment and index locations,
    // using variant of single-word Wang/Jenkins hash.
    // TODO(kevinb): use Hashing/move this to Hashing?
    h += (h << 15) ^ 0xffffcd7d;
    h ^= h >>> 10;
    h += h << 3;
    h ^= h >>> 6;
    h += (h << 2) + (h << 14);
    return h ^ (h >>> 16);
  }

  /**

   * @param h hash code
   */
  static int rehash(int h) {
    // Spread bits to regularize both segment and index locations,
    // using variant of single-word Wang/Jenkins hash.
    // TODO(kevinb): use Hashing/move this to Hashing?
    h += (h << 15) ^ 0xffffcd7d;
    h ^= h >>> 10;
    h += h << 3;
    h ^= h >>> 6;
    h += (h << 2) + (h << 14);
    return h ^ (h >>> 16);
  }

  /**