This is work (_stream and _listener are private fields, initialising into task):

    public void Stop()
    {
        if (_listenTask != null)
        {
            _source.Cancel();

            try
            {
                _stream?.Close();
            }
            catch (Exception)
            { }

            try
            {
                _listener?.Stop();
            }
            catch (Exception)
            { }

            while (!(_listenTask.IsCanceled || _listenTask.IsCompleted || _listenTask.IsFaulted))
            {
                Thread.Sleep(1);
            }

            _listenTask = null;
            _source = null;
        }
    }