Default partitioning logic is not compatible with Java and kafkajs libraries

[themarster]

After switching to platformatic kafka, we have found that messages are being published to different partitions than they were before.
This breaks compaction and cases of multiple producers with different tech stacks.
The murmur2 implementation seems to be compatible in all three cases, however after applying the murmur2 function, the java and kafkajs libraries use a toPositive implementation as follows:
const toPositive = x => x & 0x7fffffff
(See https://github.com/tulios/kafkajs/blob/master/src/producer/partitioners/legacy/partitioner.js#L12 and https://github.com/apache/kafka/blob/0.10.2/clients/src/main/java/org/apache/kafka/common/utils/Utils.java#L770)
The platformatic library instead uses this:
partition = murmur2(key) >>> 0
(https://github.com/platformatic/kafka/blob/main/src/clients/producer/producer.ts#L337)

If this is intended, it should possibly be added to the readme.

[ShogunPanda]

Hi!
To solve your issue you could provide a custom partitioner that uses murmur2 and then applies your normalization.
Would you like to send a PR to fix the documentation?

[kibertoad]

@ShogunPanda Are there any benefits to platformatic divergent implementation? is it more performant?