Detect when layer is visible?

[mglonnro]

Cheers,

I'm loading a map with a ShapeSource containing north of 50.000 SymbolLayers. The symbols are first fetched from a uri, and then added to the map. The whole process takes about ~10 sec, of which the fetching is ~2 sec.

What I want to do, is render an <ActivityIndicator /> until the symbols actually have appeared on the map. I can get reasonably close by using onMapIdle, but there's still about ~1 sec from onMapIdle firing and the symbols appearing (they are fading in nicely, though :)).

Is there any way for me to detect when the symbols are actually visible on the map?