Call `cb_timer_update_line_numbers()` when switching buffers. A timer is required because the bar item is refreshed before the new buffer is actually displayed, so ``win_chat_height`` would refer to the old buffer. Using a timer refreshes the item after the new buffer is displayed.
(data, signal, signal_data)
source not stored for this graph (policy: none)
nothing calls this directly
no outgoing calls
no test coverage detected