Method constructor

demo/SharedService/SharedService.js:34–54

* @param {string} serviceName * @param {() => MessagePort|Promise } portProviderFunc

(serviceName, portProviderFunc)

   * @param {() => MessagePort|Promise<MessagePort>} portProviderFunc 
   */
  constructor(serviceName, portProviderFunc) {
    super();

    this.#serviceName = serviceName;
    this.#portProviderFunc = portProviderFunc;

    this.#clientId = this.#getClientId();

    // Connect to the current provider and future providers.
    this.#providerPort = this.#providerChange();
    this.#clientChannel.addEventListener('message', ({data}) => {
      if (data?.type === 'provider' && data?.sharedService === this.#serviceName) {
        // A context (possibly this one) announced itself as the new provider.
        // Discard any old provider and connect to the new one.
        this.#closeProviderPort(this.#providerPort);
        this.#providerPort = this.#providerChange();
      }
    }, { signal: this.#onClose.signal });

    this.proxy = this.#createProxy();
  }

  activate() {
    if (this.#onDeactivate) return;