我见过flink consumer，它具有以下属性：在程序开始时，flink以大约400条消息/秒的速度消耗记录，但后来随着numbuffersout超过1000000，数据速率下降到200条消息/秒。我已经将parallelism设置为1，它是基于avro的消费者，检查点被禁用。还有人面临同样的问题吗？

Properties kafkaProps = new Properties();
        kafkaProps.setProperty("bootstrap.servers", bootstrapAddress);
        kafkaProps.setProperty("zookeeper.connect", zookeeperConnect);
        kafkaProps.setProperty("group.id", groupId);
        kafkaProps.setProperty(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, "true");
        kafkaProps.setProperty(ConsumerConfig.AUTO_COMMIT_INTERVAL_MS_CONFIG, "5000");
        ConfluentAvroDeserializationSchema deserializer = new ConfluentAvroDeserializationSchema(schemaRegURL);
        FlinkKafkaConsumer010<GenericRecord> flinkKafkaConsumer = new FlinkKafkaConsumer010<GenericRecord>(topic, deserializer, kafkaProps);
        flinkKafkaConsumer.setStartFromLatest();
        FlinkConnectorRateLimiter rateLimiter = new GuavaFlinkConnectorRateLimiter();
        rateLimiter.setRate(12000000L);
        flinkKafkaConsumer.setRateLimiter(rateLimiter);
        flinkKafkaConsumer.setCommitOffsetsOnCheckpoints(false);

//ConfluentAvroDeserializationSchema
    @Override
    public GenericRecord deserialize(byte[] message) {
        if (kafkaAvroDecoder == null) {
            System.out.println("Kafka serizlier");
            SchemaRegistryClient schemaRegistry = new CachedSchemaRegistryClient(this.schemaRegistryUrl, this.identityMapCapacity);
            this.kafkaAvroDecoder = new KafkaAvroDecoder(schemaRegistry);
        }
        return (GenericRecord) this.kafkaAvroDecoder.fromBytes(message);
    }