TURN client wont close the socket

[magniff]

In my application, I've observed that when a TURN server is used as a proxy, numerous UDP sockets remain open even after all network activities have ceased and there are no clients connected. I've pinpointed the issue to this section of code: https://github.com/webrtc-rs/webrtc/blob/master/turn/src/client/mod.rs#L235-L241. The problem appears to stem from the recv_from method, which lacks a timeout mechanism.

To address this issue, I'm considering implementing a timeout for the recv_from call to ensure it doesn't hang indefinitely. Here's a proposed solution:

let (n, from) = match tokio::time::timeout(timeout_duration, conn.recv_from(&mut buf)).await {
    Ok(Ok((n, from))) => (n, from), // Successfully received data within the set timeout
    Ok(Err(err)) => {
        log::debug!("Encountered a network error: {}", err);
        break;
    }
    Err(_) => {
        log::debug!("The recv_from call timed out after {:?}", timeout_duration);
        break; // Terminating the loop if a timeout is encountered
    }
};

which works for me, not sure if that'd work for you. Any thoughts on that?

[kenaniah]

@rainliu what are your thoughts on the above? Would you like a PR for this?