[vore]

I think it's all a matter of how you want to draw the line: do you want to expose the underlying runtime to the consumer, or do you want to make green threads look like real threads? I'm more sympathetic to the latter, because real threads with kernel scheduling don't have function coloring and are even less predictable in when they yield, so why can't my language runtime (e.g. in Python) just pretend they're kernel threads?

I give a pass to Rust for this one though, since it would need a more heavyweight runtime with green threads to deal with this.