Pretty much. You get to pretend inside your fibers that you're actually running threads. IIRC (it's been a while) you also get proper stack trace when something barfs, the importance of which cannot be overstated.
What are they though? Is this a library for an existing language? A runtime scheduler like the one that does goroutines in Go? If it were open sourced, how would I use it?
It’s just a library that allows easier development of C++ servers in the synchronous, thread-per-requests style, similar to working in Go but a bajillion times better because it’s not in Go.