private RecordAccumulator createTestRecordAccumulator(int batchSize, long totalSize, Compression compression, int lingerMs) {
        int deliveryTimeoutMs = 3200;
        return createTestRecordAccumulator(deliveryTimeoutMs, batchSize, totalSize, compression, lingerMs);
    }
Return the offset delta when there is no key.
clients/src/test/java/org/apache/kafka/clients/producer/internals/RecordAccumulatorTest.java