Incorrect timeout

[DavidEichmann]

When setting a session timeout, the behaviour seems incorrect! Consider this code that connects via ssh and runs sleep 30 && echo DONE to sleep for 30 seconds:

    let username = "...";
    let ip = "...";
    let password = "...";

    let timeout_ms = 15_000;
    let command = "sleep 30 && echo DONE"

    let tcp = std::net::TcpStream::connect(format!("{ip}:22"))?;
    let mut sess = Session::new()?;
    sess.set_timeout(timeout_ms);
    sess.set_tcp_stream(tcp);
    sess.handshake()?;
    sess.userauth_password(&username, &password)?;
    if !sess.authenticated() {
        return Err(anyhow!("Failed to connect by SSH"));
    }

    // Connect channel in exec mode.
    let mut channel = sess.channel_session()?;
    channel.handle_extended_data(ssh2::ExtendedData::Merge)?;
    println!("running command: {command}");
    channel.exec(command)?;
    let mut output = String::new();
    channel.read_to_string(&mut output)?;
    channel.close()?;
    channel.wait_close()?;
    let exit_status = channel.exit_status()?;

    sess.disconnect(
        Some(DisconnectCode::ByApplication),
        "Finished Running Script",
        None,
    )?;

    println!("SUCCESS");
    println!("exit code: {exit_status}");
    println!("output:\n{output}");

I expect the session to timeout after 15 seconds, but instead it times out after 30 seconds! If instead we have timeout_ms = 5_000 then it times out after 15 seconds. From my experimenting I think the current (unexpected) behaviour is as follows:

If the command blocks for duation t and t < timeout then return Ok
If the command blocks for duation t and t > 3*timeout then return a timeout error at time 3*timeout.
If the command blocks for duation t and timeout < t < 3*timeout_ms then return a timeout error at time t

I'm running on windows and with ssh2-0.9.4