/** The HTTP {@code Expires} header field name. */
  public static final String EXPIRES = "Expires";
  /** The HTTP {@code Last-Modified} header field name. */
  public static final String LAST_MODIFIED = "Last-Modified";
  /** The HTTP {@code Link} header field name. */
  public static final String LINK = "Link";
  /** The HTTP {@code Location} header field name. */
  public static final String LOCATION = "Location";