[BUG] close channel with pending responses

[xuesongxs]

Describe the bug
Pulsar v2.8.1, KOP v2.8.1.30

To Reproduce
Steps to reproduce the behavior:

1. Start kop with broker
2. bin/kafka-producer-perf-test.sh --topic test-topic --num-records 1000000 --record-size 1000 --throughput -1 --producer-props bootstrap.servers=XXXX:9092
3. broker.log
   4.The rate at which Kafka producers write to topics is unstable, and connections are closed every 1 minute
   
4. See error
   

Expected behavior
The rate at which kafka producers write to the topic is stable, and the connection between kafka producers and kop will not be closed.

Screenshots
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Additional context
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