ruby-threach binary package in Ubuntu Focal amd64

 An addition to the Enumerable Ruby module that allows easy use of threaded
 each and each-like iterators. It's a very simple producer-consumer model.
 .
 If you're using stock (MRI) ruby -- you probably shouldn't bother with threach
 unless you're doing IO-intensive stuff. It'll just slow things down. But if
 you're using a ruby implementation that has real threads, like JRuby, this
 will give you relatively painless multi-threading.

Source package