From torch._C import * walkthrough

What’s happened when I call from torch._C import * ? In the file, torch._C as a C extended module being added. In my opinion, when from torch._C import * being called, it should jump to torch/csrc/stub.c file and execute PyInit__C funciton immediately. But the fact is that TorchLibraryInit is reached before PyInit__C. So how does pytorch step into C++ world ?