the number of items in the channel corresponds to the number of active uses,
the capacity of the channel corresponds to the maximum number of simultaneous uses,
sending an item acquires the semaphore, and receiving an item releases
the semaphore.
This is a common idiom for limiting concurrency.
</p>

<p>
This program starts a goroutine for every entry in the work list, but the

                writer.println("<a name=\"sec_$version\"></a>")
                writer.println(
                    "<h2>Incubating since $version (${versions[version]?.run { "released on $this" } ?: "unreleased"})</h2>"
                )
                writer.println("<ul>")
                incubatingDescriptions.sorted().forEach { incubating ->