-- | The port that is used by the Listener.
lPort :: Lens' Listener (Maybe Int)
lPort = lens _lPort (\s a -> s { _lPort = a })
lPort :: Lens' Listener (Maybe Int)
lPort = lens _lPort (\s a -> s { _lPort = a })
lPort = lens _lPort (\s a -> s { _lPort = a })