ClusterTopic provides reliable Publish/Subscribe message model
communication between the nodes in the Resin cluster.
Following example shows how to make two nodes in resin cluster
communicate between each other using cluster topic.
ClusterTopic sends out a SubscribeTopic message to Triad
Traid stores all the topic subscriptions
Message Producer sends out a TriadTopicMessage to the Triad
Triad node sends out TriadTopicMessage to all the topic subscribers