title: Is key required as part of sending messages to Kafka?
body: <pre class="lang-java prettyprint-override"><code>KeyedMessage&lt;String, byte[]&gt; keyedMessage = new KeyedMessage&lt;String, byte[]&gt;(request.getRequestTopicName(), SerializationUtils.serialize(message)); 
  producer.send(keyedMessage);
  </code></pre>
  
  <p>Currently, I am sending messages without any key as part of keyed messages, will it still work with <code>delete.retention.ms</code>? Do I need to send a key as part of the message? Is this good to make key as part of the message?</p>