code: public void send( String topic, String message, LogbackFormatter formatter, long timeoutMillis )
                      throws IOException, InterruptedException, ExecutionException, TimeoutException
      {
          Future future = doKafkaSend( topic, message, formatter );
          if ( future != null )
          {
              future.get( timeoutMillis, TimeUnit.MILLISECONDS );
          }
      }
docs: Blocking send with a logback formatter to format the message.