miniupnpc-libevent :

UPnP IGD control point (ie client) using libevent

http://libevent.org
https://github.com/libevent/libevent

The UPnP Event code needs SUBSCRIBE / UNSUBSCRIBE / NOTIFY HTTP methods.
Implementation is in progress in libevent HTTP code :
libevent/libevent#327


TODO : improve error handling / reporting