MQTT version 3.1 compatible message broker

 This is a message broker that supports version 3.1 of the MQ Telemetry
 Transport protocol.
 .
 MQTT provides a method of carrying out messaging using a publish/subscribe
 model. It is lightweight, both in terms of bandwidth usage and ease of
 implementation. This makes it particularly useful at the edge of the network
 where a sensor or other simple device may be implemented using an arduino for
 example.