Supplier<T> delegate) {
    return new ThreadSafeSupplier<>(delegate);
  }

  @J2ktIncompatible
  private static final class ThreadSafeSupplier<T extends @Nullable Object>
      implements Supplier<T>, Serializable {
    final Supplier<T> delegate;

    ThreadSafeSupplier(Supplier<T> delegate) {
      this.delegate = checkNotNull(delegate);
    }

    @Override