An ArrayBuffer is transferred (via structuredClone with transfer, or postMessage). What happens to existing typed array views over it, per the detachment semantics?
const buf = new ArrayBuffer(8);
const view = new Uint8Array(buf);
view[0] = 9;
structuredClone(buf, { transfer: [buf] });
const r = [buf.byteLength, view.length, view[0]];