*/
  HTTP_3("h3"),
  ;

  /**
   * Returns the string used to identify this protocol for ALPN, like "http/1.1", "spdy/3.1" or
   * "h2".
   *
   * See also [IANA tls-extensiontype-values][iana].
   *
   * [iana]: https://www.iana.org/assignments/tls-extensiontype-values
   */
  override fun toString(): String = protocol

  companion object {
    /**
     * Returns the protocol identified by `protocol`.