The code is basiclly ported from offical ChatSample to Xcode. Precompiled binary lib for MacOSX is included, which you can find in the lib directory.
ChatClient client side code using RakNet, shows how to establish client side connection and send message in RELIABLE_ORDER mode.
ChatServer server side code, hosting client connections, both server-side and client-side shows how to use ping and checking connection statics.
include contains all header files for RakNet, cp from RakNet's source directory
lib contains precompiled binary static lib for RakNet, it was build from source code from github on 20150108, for RakNet4.
The source code for RakNet can be found here https://github.com/OculusVR/RakNet
Note that you can not use free RakNet for commercial usage beyond 100K budget, check out the detailed usage licence from the offical site http://www.jenkinssoftware.com/