code: public Properties producerConfig() {
          Properties props = new Properties();
          props.put("bootstrap.servers", connectionString());
          props.put("acks", "all");
          props.put("batch.size", "100");
          props.put("client.id", "kafka-junit");
          props.put("request.timeout.ms", "5000");
          props.put("max.in.flight.requests.per.connection", "1");
          props.put(ProducerConfig.RETRIES_CONFIG, Integer.MAX_VALUE);
          props.put(ProducerConfig.LINGER_MS_CONFIG, 0);
  
          return props;
      }
docs: Create a minimal producer configuration that can be used to produce to this broker
  
  @return Properties