TCP: Waiting for a socket to enter the `closed` state

In the following pseudocode (assuming the definitions in wit-0.3.0-draft):

let sock = TcpSocket::new(IpAddressFamily::Ipv4);
let bind_addr = /* some valid IPv4 address */;
sock.bind(bind_addr);
let data = /* create a new stream */;
sock.send(data);
data.close();
// Wait for `sock` to transition to the `closed` state

what would I add after the last comment if I wanted to add subsequent code that depended on sock being in the closed state? I assume that data.close() terminates the connection ("Closing the stream is equivalent to calling shutdown(SHUT_WR) in POSIX", comment on send()), but the older version of the TCP operational semantics doc says that the transition from connected to closed is asynchronous if the connection terminates. So what's the mechanism for waiting for this transition to occur?

Start with the TcpSocket::new, bind, send, and data.close() sequence in issue #704, then read the linked wit-0.3.0-draft send() comment and the older TCP operational semantics document. Done means documenting the mechanism, if one exists, for waiting until the socket reaches closed after the stream is closed.