Block any user interaction in GTK4+

Question

Many GUI libraries requests to process functions inside the main thread. I need to call/delegate routines/events to other threads. Problem is, setting text of text area in Gtk4+ will block in this case and I would not to process any other events, when my event is processed. What I do:

1. Delegate event to another thread,
2. Create event source (idle)and context, attaching source to context,
3. Running loop of context,
4. My special function will delegate events (callbacks) to this source.

I think problem is there should be main loop, when setting text to gtk's text area.