@Override
                    public MetricGroup getMetricGroup() {
                        return readerContext.metricGroup().addGroup("deserializer");
                    }
Get a kafkaSourceBuilder to build a {@link KafkaSource}.

@return a Kafka source builder.
inlong-sort/sort-flink/sort-flink-v1.18/sort-connectors/kafka/src/main/java/org/apache/inlong/sort/kafka/source/KafkaSource.java