[go-nuts] the offical timing out blog post should get improve

http://blog.golang.org/go-concurrency-patterns-timing-out-and this is the
first result in googling "golang timeout"

select {
case <-ch:
// a read from ch has occurred
case <-timeout:
// the read from ch has timed out
}


but this code is a big trap of goroutine leaking. when read occurred first
the timeout goroutine will leak, and vice versa. I write some code which
reference this artcle, and found and fixed this bug a long time after that.
It would help lots of new comers if this artcle also include code to avoid
goroutine leak.