constructor (type, eventInitDict = {}) {
    const prefix = 'CloseEvent constructor'
    webidl.argumentLengthCheck(arguments, 1, prefix)

    type = webidl.converters.DOMString(type, prefix, 'type')
    eventInitDict = webidl.converters.CloseEventInit(eventInitDict)

    super(type, eventInitDict)

    this.#eventInit = eventInitDict
    webidl.util.markAsUncloneable(this)
  }
@see https://websockets.spec.whatwg.org/#the-closeevent-interface