Method constructor

packages/svelte/src/reactivity/reactive-value.js:15–18

* * @param {() => T} fn * @param {(update: () => void) => void} onsubscribe

(fn, onsubscribe)

	 * @param {(update: () => void) => void} onsubscribe
	 */
	constructor(fn, onsubscribe) {
		this.#fn = fn;
		this.#subscribe = createSubscriber(onsubscribe);
	}

	get current() {
		this.#subscribe();