Hi,
We are investigating an issue where we are unable to use the Sketch Editor until layers are loaded.
If the user has a poor cellular connection, or if the server is slow, this generates a poor UI experience.
To create a consistent repro of the issue, we have set up a fake tile server that always waits 30 seconds before returning a tile.
The linked video shows the attached code example in use
https://www.icloud.com/sharedalbum/#B0YG4VTwGGS3JE6