/**
   * The "base64" base encoding specified by <a
   * href="http://tools.ietf.org/html/rfc4648#section-4">RFC 4648 section 4</a>, Base 64 Encoding.
   * (This is the same as the base 64 encoding from <a
   * href="http://tools.ietf.org/html/rfc3548#section-3">RFC 3548</a>.)
   *
   * <p>The character {@code '='} is used for padding, but can be {@linkplain #omitPadding()

  public static final String X_POWERED_BY = "X-Powered-By";
  /**
   * The HTTP <a href="http://tools.ietf.org/html/draft-evans-palmer-key-pinning">{@code
   * Public-Key-Pins}</a> header field name.
   *
   * @since 15.0
   */
  public static final String PUBLIC_KEY_PINS = "Public-Key-Pins";
  /**
   * The HTTP <a href="http://tools.ietf.org/html/draft-evans-palmer-key-pinning">{@code

  /**
   * The "base64" base encoding specified by <a
   * href="http://tools.ietf.org/html/rfc4648#section-4">RFC 4648 section 4</a>, Base 64 Encoding.
   * (This is the same as the base 64 encoding from <a
   * href="http://tools.ietf.org/html/rfc3548#section-3">RFC 3548</a>.)
   *
   * <p>The character {@code '='} is used for padding, but can be {@linkplain #omitPadding()

  public static final String X_POWERED_BY = "X-Powered-By";
  /**
   * The HTTP <a href="http://tools.ietf.org/html/draft-evans-palmer-key-pinning">{@code
   * Public-Key-Pins}</a> header field name.
   *
   * @since 15.0
   */
  public static final String PUBLIC_KEY_PINS = "Public-Key-Pins";
  /**
   * The HTTP <a href="http://tools.ietf.org/html/draft-evans-palmer-key-pinning">{@code

   * Returns the string representation of an {@link InetAddress}.
   *
   * <p>For IPv4 addresses, this is identical to {@link InetAddress#getHostAddress()}, but for IPv6
   * addresses, the output follows <a href="http://tools.ietf.org/html/rfc5952">RFC 5952</a> section
   * 4. The main difference is that this method uses "::" for zero compression, while Java's version

   * Returns the string representation of an {@link InetAddress}.
   *
   * <p>For IPv4 addresses, this is identical to {@link InetAddress#getHostAddress()}, but for IPv6
   * addresses, the output follows <a href="http://tools.ietf.org/html/rfc5952">RFC 5952</a> section
   * 4. The main difference is that this method uses "::" for zero compression, while Java's version

   * is complete. It does so by using daemon threads and adding a shutdown hook to wait for their
   * completion.
   *
   * <p>This is mainly for fixed thread pools. See {@link Executors#newFixedThreadPool(int)}.
   *
   * @param executor the executor to modify to make sure it exits when the application is finished

   *   <li>Underscores ('_') are permitted wherever dashes ('-') are permitted.
   *   <li>Parts other than the final part may start with a digit, as mandated by <a
   *       href="https://tools.ietf.org/html/rfc1123#section-2">RFC 1123</a>.
   * </ul>
   *
   * @param domain A domain name (not IP address)
   * @throws IllegalArgumentException if {@code domain} is not syntactically valid according to

   * is complete. It does so by using daemon threads and adding a shutdown hook to wait for their
   * completion.
   *
   * <p>This is mainly for fixed thread pools. See {@link Executors#newFixedThreadPool(int)}.
   *
   * @param executor the executor to modify to make sure it exits when the application is finished

   *   <li>Underscores ('_') are permitted wherever dashes ('-') are permitted.
   *   <li>Parts other than the final part may start with a digit, as mandated by <a
   *       href="https://tools.ietf.org/html/rfc1123#section-2">RFC 1123</a>.
   * </ul>
   *
   * @param domain A domain name (not IP address)
   * @throws IllegalArgumentException if {@code domain} is not syntactically valid according to