Not sure about the term, but I know Windows has had them for almost two decades[1], so hardly a newfangled concept.

Here's[2] a fun/interesting 15 year old blog post explaining some of the use cases and pitfalls of using Win32 fibers.

[1]: https://jeffpar.github.io/kbarchive/kb/128/Q128531/ (CreateFiber)

[2]: https://docs.microsoft.com/en-us/archive/blogs/larryosterman...