how to cancel a work pool?

[plastikfan]

When you create a pool, since the api doesn't include a context, it is difficult to see how cancellation is supported in an ants worker pool.

A typical usage of the pool with func would be something like this (derived from one of the ants testcases):

	var wg sync.WaitGroup
	pool, _ := ants.NewPoolWithFunc(AntsSize, func(i ants.InputParam) {
		demoPoolFunc(i)
		wg.Done()
	})
	defer pool.Release()

	for i := 0; i < n; i++ {
		wg.Add(1)
		_ = pool.Invoke(Param)
	}
	wg.Wait()

But as I see it, there is a problem with this:

What if the pool needs to be cancelled part way through? The problem manifests itself by the fact that the client is performing a wait on the waitgroup, which could be a high number, so even if we could cancel somehow, the wait would need to be pre-empted to avoid waiting for the wait group counter to reach zero, but it won't.

I'm not sure how/if cancellation is supported so I would appreciate some enlightenment about this, thanks.