Attached is a patch that makes the performance test use either the old or new producer.
This patch includes a few other things:
1. Fix a bug in TestEndToEndLatency that lead to always giving an error about the wrong partitioner being used.
2. Fix a bug in ConsumerPerformance.scala that lead to consuming the full topic. Plus some additional cleanup in ConsumerPerformance.
3. Expose a few more options in the new ProducerPerformance.java