[BUG] Producer send callback cannot get metadata

[BewareMyPower]

Describe the bug

The Kafka producer cannot get metadata from send callback. It's caused by following code:

kop/kafka-impl/src/main/java/io/streamnative/pulsar/handlers/kop/KafkaRequestHandler.java

Lines 618 to 622 in f81f7e4

	} else {
	result.getRight().complete(new PartitionResponse(Errors.NONE));
	}
	headerAndPayload.release();
	});

The PartitionResponse only sets one field error, other fields are default value, see

    public static final class PartitionResponse {
        public Errors error;
        public long baseOffset;
        public long logAppendTime;
        public long logStartOffset;

        public PartitionResponse(Errors error) {
            this(error, -1L, -1L, -1L);
        }

To Reproduce

Let Kafka producer send with a callback:

        producer.send(new ProducerRecord(topic, 0, "hello"), (recordMetadata, e) -> {
            if (e == null) {
                log.info("send to {}", recordMetadata);
            } else {
                log.info("send failed: {}", e);
            }
        }).get();

The log:

send to topic-xyz-0@-1

Expected behavior

Producer should get the right metadata.

Additional context

Currently the offset is not continuous, so the offset is meaningless because Kafka Client uses baseOffset to generate each offset for messages.

This bug needs to be fixed after the continuous offset was implemented.