* Maximum length of a full domain name, including separators, and leaving room for the root
   * label. See <a href="http://www.ietf.org/rfc/rfc2181.txt">RFC 2181</a> part 11.
   */
  private static final int MAX_LENGTH = 253;

  /**
   * Maximum size of a single part of a domain name. See <a
   * href="http://www.ietf.org/rfc/rfc2181.txt">RFC 2181</a> part 11.
   */
  private static final int MAX_DOMAIN_PART_LENGTH = 63;

   * MD5 (128 hash bits) hash function and the given secret key.
   *
   * <p>If you are designing a new system that needs HMAC, prefer {@link #hmacSha256} or other
   * future-proof algorithms <a
   * href="https://datatracker.ietf.org/doc/html/rfc6151#section-2.3">over {@code hmacMd5}</a>.
   *
   * @param key the secret key
   * @throws IllegalArgumentException if the given key is inappropriate for initializing this MAC
   * @since 20.0
   */

 * directives. It even offers convenient constants [CacheControl.FORCE_NETWORK] and
 * [CacheControl.FORCE_CACHE] that address the use cases above.
 *
 * [rfc_7234]: http://tools.ietf.org/html/rfc7234
 */
class Cache internal constructor(
  directory: Path,
  maxSize: Long,
  fileSystem: FileSystem,
  taskRunner: TaskRunner,
) : Closeable,
  Flushable {