This test produces a large number of messages to a broker. It measures the throughput and tests
the amount of data received is expected.

To run this test, do
bin/run-test.sh

The expected output is given in expected.out. There are 2 things to pay attention to:
1. The output should have a line "test passed".
2. The throughput from the producer should be around 300,000 Messages/sec on a typical machine.