User messages functionality support
Custom protocol messages
Goes after the 48 protocol entries
Server creates and fires them
Client hooks and handles them
https://github.com/ValveSoftware/source-sdk-2013/blob/master/mp/src/game/shared/usermessages.h
https://github.com/ValveSoftware/source-sdk-2013/blob/master/mp/src/game/shared/usermessages.cpp
Edited by BlackPhrase