public async Task A_consumer_is_being_tested()
{
_harness = new InMemoryTestHarness();
_batchConsumer = new TestBatchConsumer(_harness.GetTask <Batch <PingMessage> >());
_consumer = _harness.Consumer(() => _batchConsumer, c => c.Options <BatchOptions>(o => o.SetMessageLimit(2)));
await _harness.Start();
}