Subscriber needs to unsubscribe and wait

[hmartiro]

Right now, there is an explicit pause in the disconnect() method of Subscriber. It seems hiredis requires us to unsubscribe from everything and have no more pending commands, or it gives this type of error:

speed_test_pubsub: async.c:289: __redisAsyncDisconnect: Assertion__redisShiftCallback(&ac->replies,((void *)0)) == -1' failed.`

Contact hiredis guys to see a nicer way around this? Maybe have a cv that waits until there are no more pending hiredis requests, or cancel them somehow.