exchange ->direct
queueD
connection
routingkey
consumer
channel
provider
通过routingkey和queue绑定
queueC
queueA
点对点push
queueB
virtual host用户B
queueAqueueB
exchange ->fanout
exchange->topic
exchangeA--binding-->
broker 接受分发消息
和routingkey没关系，只要和broker绑定队列
virtual host用户A
