title: Does Kafka have a batch consumer?
body: <p>The High-Level consumer API seems to be reading one message at a time.</p>
  
  <p>This could be quite problematic for the consumers if they want to process and submit those messages to other downstream consumers like Solr or Elastic-Search because they prefer to have messages in bulk rather than one at a time.</p>
  
  <p>It is not trivial to batch those messages in memory too because than the offsets in Kafka will also need to synced only when the batch is already committed otherwise a crashed kafka-consumer with uncommitted downstream messages (as in Solr or ES) will have its offsets updated already and hence loose messages.</p>
  
  <p>The consumer could consume messages more than once if it crashes after committing messages downstream but before updating message offsets.</p>
  
  <p>If Kafka consumes messages in batch, then some pointers to the code/documentation would be much appreciated.</p>
  
  <p>Thanks!</p>