THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
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PR: https://github.com/apache/kafka/pull/12545
JIRA: Jira server ASF JIRA serverId 5aa69414-a9e9-3523-82ec-879b028fb15b key KAFKA-14944
Motivation
Currently we use Deserializer#deserialize(String topic, Headers headers, byte[] data) in CompletedFetch#parseRecord(TopicPartition, RecordBatch, Record) to deserialize key&value, we first call Utils.toArray(ByteBuffer) to convert ByteBuffer into byte[] and then call Deserializer#deserialize(String topic, Headers headers, byte[] data) which will cause memory allocation and memory copying.
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