@SuppressWarnings("NullableOptional") // Null passthrough is reasonable for type conversions
  @IgnoreJRERequirement // Users will use this only if they're already using Optional.
  public static <T> @Nullable Optional<T> fromJavaUtil(
      java.util.@Nullable Optional<T> javaUtilOptional) {
    return (javaUtilOptional == null) ? null : fromNullable(javaUtilOptional.orElse(null));
  }

  /**