The most straightforward use of a thread pool is to execute some number of jobs, then wait for their completion. I had this need just now and reached for this crate, but I didn't realize that you could wait for all jobs to be done with the join() method, so I went looking for a countdown latch crate instead.

The barrier example sort of suggests that using some other syncronization primitive is a preferred way to wait for all jobs to be done. I think having a dedicated example to show the basic "spawn some workers then wait for them to complete" use case might help avoid confusion.