* the values are optional and names may be repeated.
 *
 * ### Fragment
 *
 * The fragment is optional: it can be null, empty, or non-empty. Unlike host, port, path, and
 * query the fragment is not sent to the webserver: it's private to the client.
 *
 * ## Encoding
 *
 * Each component must be encoded before it is embedded in the complete URL. As we saw above, the