[Catalyst] Handling long-running processes (was Re: Logging is not immediate)

[Chris]

>
> I'm curious to know how other people approach this issue.
>
> Also, what do you think about the polling approach vs a (background)
> connection that stays connected waiting for the completion signal?
>

I've found polling much simpler to implement (and test) as it doesn't
require anything particularly special on either client or server-side.
It means a bit more delay - the polling period - before the user gets
the result, but for our use-case (generating reports and download
files) this hasn't been an issue. I've seen some stuff suggesting that
polling leads to higher server load, but again it hasn't been an issue
in our low-traffic web-apps.

- Chris