The first approach I took was for an actual generic proc type to define it:

https://github.com/mattsah/mininim-core/blob/main/src/mininim/dic.nim#L10

This originally looked more like:

`DelegateHook[T] = proc(self: typedesc[T], app: var App): T`

Then I was trying to simply pass in the symbol from the class that needed the
delegate e.g.:  `builder: build`

Then back in the `app.get()` proc trying to do something along the lines of:
`delegate.Delegate.builder(T, app)`

The problem is trying to `var builder: DelegateHook` on the `Delegate` class
basically said an object couldn't be a non concrete type.