Code review comment for lp:~cprov/adt-result-checker/qos

Paul,

prefetch_count=0 (along with default prefetch_size=0) means the consumer is telling rabbit to "reserve as many messages as you can for me", which is bad for our multi-worker environment, because workers will compete to reserve messages, but will take quite a long time to process (acknowledge)them. Other workers will starve and be idle most of the time.

prefetch_count=1, means that only one single message will be given to workers at time. So until the test is done, other messages in the queue will be available to other workers to pick them up.

See a more appropriate description at https://www.rabbitmq.com/consumer-prefetch.html