static List<Result> await(List<CompletableFuture<Result>> promises) throws MultiFeedException {
        return Helper.await(promises);
    }
Waits for all feed operations to complete, either successfully or with exception.
@throws MultiFeedException if any operation fails
@return list of results with the same ordering as the {@code promises} parameter
vespa-feed-client-api/src/main/java/ai/vespa/feed/client/FeedClient.java