title: is paho.mqtt.cpp just a wrapper of paho.mqtt.c,what is different between the two?
body: <p>paho.mqtt.cpp refer to c version, from aspective of MQTT protocol, the two implements have almost same feature.so why use cpp version to wrapper c version? what is the advantage of cpp version than c version in feature、performance..etc?
  could someone please give me the answer or provide some materials? I am eager to know for the choice of the two library.</p>