`agora_rtc_engine` has a very slow cold start on iOS 18. The first call to `RtcEngine.initialize()` can block for ~47-62 seconds. After it completes once, later calls are fast.

On iOS 18 first launch / cold start, RtcEngine.initialize() takes ~47-62 seconds before the Flutter app can proceed to join the channel.

Impact
The first call attempt appears stuck or fails because call/session timeouts fire before Agora finishes initializing. The second call works because the engine/audio stack is already warmed.

Workaround
We currently pre-warm the Agora engine earlier in the app, but this is only a workaround. The SDK should not block this long on first initialization.