The directory Source/ThirdParty/protobuf contains the includes and libraries for protobuf (just copied) as well as a build script that adds these and also defined GOOGLE_PROTOBUF_NO_RTTI=1 to disable RTTI. Source/ProtobufExample contains the generated code based on the address book example. The generated c++ file had some warnings disabled to make it compile as UE4 treats these as errors.
#pragma warning(disable: 4125)
#pragma warning(disable: 4668)
#pragma warning(disable: 4577)
Furthermore because of a bug in UE4 4.21 the source file had its extension renamed from .cc to .cpp, although this is not necessary anymore in 4.22. Source/ProtobufExample/ProtobufExampleGameModeBase.cpp contains code making use of the address book class.
Currently only contains binaries for Windows 64 bit.