List<String> actual = new CopyOnWriteArrayList<>();
ExecutorService service = Executors.newSingleThreadExecutor();
Future<?> consumingTask = service.submit(() -> {
  while (!Thread.currentThread().isInterrupted()) {
    ConsumerRecords<String, String> records =
      consumer.poll(Duration.ofMillis(100));
    for (ConsumerRecord<String, String> rec : records) {
      actual.add(rec.value());
    }
  }
});

...

try {
  Awaitility.await().atMost(5, Seconds)
    .until(() -> List.of("A", "B").equals(actual));
} finally {
  consumingTask.cancel(true);
  service.awaitTermintion(200, MILLISECONDS);
}