I've commented several times in various forums that basically every
time I've seen the “worker goroutine” pattern in Go, there has turned
out to be a cleaner implementation using semaphores.
This change adds a simple such example. (For more complex usage, I
would generally pair the semaphore with an errgroup.Group.)
Change-Id: Ibf69ee761d14ba59c1acc6a2d595b4fcf0d8f6d6
Reviewed-on: https://go-review.googlesource.com/75170
Reviewed-by: Ross Light <light@google.com>
