It has a lot of overlaps with other network frameworks such as OkHttp, AFNetworking, cronet, etc., but I think it main contributions are these two components:

Xlog: in memory mmap log for fast logging and also supports encryption. Xlog log enables them to log everything fast and "safely" even in production build to quickly identify bugs.

STN: short and long TCP connection manager, which is optimized for various networks in China.

Plus other network utilities to make development easier.