function Sleep() {
    return new Promise(resolve => setTimeout(resolve, 10));
}

// introduces async getter and setter syntax
class A {
    #a;
    constructor(a) {
        this.#a = a;
    }
    get async value() {
        await Sleep();
        return this.#a;
    }
    set async value(value) {
        await Sleep();
        this.#a = value;
    }
}

// New ~= syntax returns a promise for an async setter.

async function G() {
    const a = new A(1);
    const b = new A(2);
    const bValue = await b.value;
    const aValue = await a.value;
    await a.value ~= bValue;
    await b.value ~= aValue;
}

// Destructuring syntax if the left is an array or object
// ~= returns an array of promises
async function G() {
    const a = new A(1);
    const b = new A(2);
    await.all [a.value, b.value] ~= [await b.value, await a.value];
}

// What about for object destructuring? Unsure.