vibe.d - asynchronously wait() for process to exit

[Vladimir Panteleev via Digitalmars-d-learn]

On Monday, 20 June 2016 at 16:16:32 UTC, Steven Schveighoffer 
wrote:
> What is the OS support for waitid 
> (http://man7.org/linux/man-pages/man2/waitpid.2.html)? Seems to 
> have support for async waiting of multiple processes (at least 
> it can return immediately if no child has exited). One 
> consideration is how responsive you need to be to a process 
> exiting -- is it ok for example to be notified 500ms after the 
> process exits? If so, you can interleave timed waits for socket 
> data with a check to see if any process exits. I've done this 
> in the past for such things. I don't know how well this works 
> for libevent though.

std.process has tryWait() if polling were acceptable, but I would 
really like to avoid it. Or have I misunderstood?