title: KafkaTestUtils.getRecords() returns only first sent record
body: <p>Sending 4 records:</p>
  
  <pre><code>producer.send(new ProducerRecord&lt;&gt;("my-topic", 0, "key1", "value1"));
  producer.send(new ProducerRecord&lt;&gt;("my-topic", 0, "key2", "value2"));
  producer.send(new ProducerRecord&lt;&gt;("my-topic", 0, "key3", "value3"));
  producer.send(new ProducerRecord&lt;&gt;("my-topic", 0, "key4", "value4"));
  </code></pre>
  
  <p>Using KafkaTestUtils.getRecords() get only first sent record;</p>
  
  <pre><code>final ConsumerRecords&lt;String, OrderBookViewItem&gt; records = KafkaTestUtils.getRecords(consumer, 10000);
  </code></pre>
  
  <p>Using consumer.poll() get all 4;</p>
  
  <pre><code>final Iterable&lt;ConsumerRecord&lt;String, OrderBookViewItem&gt;&gt; records = consumer.poll(1000).records("my-topic");
  </code></pre>
  
  <p>How to tune KafkaTestUtils to return all records or it is bug?</p>