Third Party module in project folder

Whats the best folder structure for adding third party modules to the project folder?


Im still playing with creating a simple MMO game using UE4 (personal challenge). Currently im using a threaded sockets sender/receiver in UE4 based on the MultichannelTcpSocket of the Engine to have async network with my server. But im having some issues with the FSocket limitations so want to create a boost asio socket module for the Engine. I want this third party module being part of the project, not the Engine source folder.

Also been trying to figure out how to get a standalone application like the slateviewer up and running in the project folder.