WebTransport: closed property

const url = "https://example.com:4999/wt";
async function initTransport(url) {
  // Initialize transport connection
  const transport = new WebTransport(url);
  // The connection can be used once ready fulfills
  await transport.ready;
  // …
}
// …
async function closeTransport(transport) {
  // Respond to connection closing
  try {
    await transport.closed;
    console.log(`The HTTP/3 connection to ${url} closed gracefully.`);
  } catch (error) {
    console.error(`The HTTP/3 connection to ${url} closed due to ${error}.`);
  }
}