How-to DI when running custom function in a standard workflow with Logic Apps

[springcomp]

I’m familiar with

• In-Process Function Apps which run within the Azure Functions runtime host.
• Isolated Worker Function Apps which run as a standalone process and communicate with the Azure Functions runtime host using gRPC.

In both cases, it is really easy to implement DI in either a Startup class or from the Main EXE entry-point.

The problem is that we seem to not have that level of control when using custom functions integrated with Standard Logic Apps.
There, the function app runs "in-process" within the Logic Apps runtime process (which itself runs isolated from the functions runtime host).

How is it possible to implement a startup-like class for such scenarios ?