WKComplications

Minimum Reproducible Example app to demonstrate the issue with WidgetKit complications not updating (watchOS 9/10)

• If the watch app is in the foreground, data is transmitted from the companion iPhone app immediately and content is updated in both app and widgets on the watch.
• If the watch app is in the background (or hasn't been launched), then there is simply no data transfer happening between devices, which leads to stale data in watch widgets.
• iPhone app has two buttons to submit value to the watch: the top one submits value via the fast, but unreliable channel, and the bottom one uses complication-related data transfer API, which in theory should transfer data even if the watch app is in the background.
• OSLog for used for logging, so it is possible to observe communication logs in Console app.