kafka-connect中consumer初始化

在WorkerSinkTask.java的createConsumer()方法中：

Map<String, Object> props = new HashMap<>();

        props.put(ConsumerConfig.GROUP_ID_CONFIG, "connect-" + id.connector());   # consumer-group-id
        props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG,
                Utils.join(workerConfig.getList(WorkerConfig.BOOTSTRAP_SERVERS_CONFIG), ","));
        props.put(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, "false");   # 自動提交offset
        props.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");   # 重置offset的位置
        props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.ByteArrayDeserializer");
        props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.ByteArrayDeserializer");

        props.putAll(workerConfig.originalsWithPrefix("consumer."));