Lets talk about fibers

[via Digitalmars-d]

I mostly agree with what you wrote, but I'd like to point out 
that it's probably safe to move some kinds of fibers across 
threads:

If the fiber's main function is pure and its parameters have no 
mutable indirection (i.e. if the function is strongly pure), 
there should be no way to get data races.

Therefore I believe we could theoretically support moving such 
fibers. But currently I see no way how most fibers can be made 
pure, after all you want to do IO in them. Of course, we could 
forego the purity requirement, but then the compiler can no 
longer support us.