loadPersistentStores / async - await support

In Xcode beta 13, the documentation of NSPersistentContainer.loadPersistentStores(completionHandler:) goes like:

You can call this method from synchronous code using a completion handler, as shown on this page, or you can call it as an asynchronous method that has the following declaration: func loadPersistentStores() async throws -> NSPersistentStoreDescription

However I couldn't call it like that as it complains about a Missing argument for parameter 'completionHandler' in call. E.g.:

do {
    try await container.loadPersistentStores()
} catch {
    // Handle error
}

Was it intentionally left aside? Perhaps it is to be added in future Xcode 13 versions?