Add support for app level initialization logic

e.g. in this thread, the user needs to call ThreadPool.SetMinThreads, and currently we have no good place to make App Domain init time calls.

Of course, that gives user potential to make some bad calls, but that’s a small concern compared to the scenarios that can unblock (and the could make the same calls in a function anyway).

[erikschlegel]

Hey - just wanted to revisit the discussion to see if an app level Azure Function init hook feature is on the horizon?

[contractorwolf]

is there some documentation of the Azure Function lifecycle? I am imagining that there is a server that is hosting the individual functions and the first request loads your function (executing the require statements, the code inline before the export and then instantiating the export) and then holds that function up for an indeterminate amount of time (AWS was 2-5 minutes with their Lambda service). When a second request comes in if there is a live function running it can respond to the request (using that instance initialization parameters) it does, if not it starts a new one up. Please correct me if I am mistaken, I want to understand this better.