pull mode consume history message very slow

[UnderTreeTech]

First I produce 1k msg to broker, then I run the examples/consumer/pull/pull.go code with minor changes (only start one goroutine to consume), just like

for i := 0; i < 1; i++ {
		go func() {
			for {
				pull()
			}
		}()
	}

There the consume rate is very slow, every pull will block about 25s. But if modify the suspend param to false at https://github.com/apache/rocketmq-client-go/blob/f4875c1bbca66be050ec71359a8b447e0b63e743/consumer/pull_consumer.go#L445 the consume rate comes fast.

[wupeaking]

I have same issue.