public DataCarrier consume(Class<? extends IConsumer<T>> consumerClass,
                               int num,
                               long consumeCycle,
                               Properties properties) {
        if (driver != null) {
            driver.close(channels);
        }
        driver = new ConsumeDriver<T>(this.name, this.channels, consumerClass, num, consumeCycle, properties);
        driver.begin(channels);
        return this;
    }
set consumeDriver to this Carrier. consumer begin to run when {@link DataCarrier#produce} begin to work.

@param consumerClass class of consumer
@param num           number of consumer threads
@param properties    for initializing consumer.
oap-server/server-library/library-datacarrier-queue/src/main/java/org/apache/skywalking/oap/server/library/datacarrier/DataCarrier.java