title: KafkaTemplate send ordering
body: <p>When using KafkaTemplate's send() method and the ListenableFuture is returned. And we wait by calling the future's get() method.</p>
  <p>Does this send the message straight away? Does this take in consideration the linger.ms or batch size (buffer it)?</p>
  <p>If we iterate through a list of Kafka messages and block on each send() via the future's get, will it guarantee the order (with the same key) arriving on the topic?</p>