configure method
- required String userId,
Initialize the Purchases SDK. Idempotent and concurrent-safe — a second call while the first is in flight awaits the same future. On failure the stored future is discarded so a later call (e.g. after sign-in retry) gets a fresh attempt instead of reusing the failed one.
Implementation
Future<void> configure({required String userId}) {
final existing = _configureFuture;
if (existing != null) return existing;
final future = _doConfigure(userId);
_configureFuture = future;
return future;
}