Reactive Slick

Here's the ongoing work on Reactive Slick.

/cc @cvogt for review later
The hard part for users is tracking the effects and making sure stuff runs against the correct endpoint. So built-in effect tracking would indeed be very helpful. Runtime may be enough. By putting a custom layer in front of the entry points you could implement master/slave switching for whole actions.

It would however require more upfront architectural thought and understanding by users, which may overburden some development situations. Also, how about actions that are run with several individual sessions, can we support correct scheduling each of them efficiently as well? I can see that users with the necessary effort can get close to out-of-the-box support using a custom solution.

Do you expect out-of-the-box support to be hard to implement? It appears rather easy to me. The hardest part would be making some smaller API design decisions. If we put it off now, there is a good chance we never get to it. But if you really think it is too much, we won't die without it.