Accessing Rendering Context and Main Rendering Loop?

Hi!
Does anyone know if I can access the main rendering loop of a Unity app for Android? Or it’s well hidden behind the unity library?

I need to integrate a 3rd party stereoscopic library that has a JNI interfaced code for it’s C code to be able to interact
with the library from Java. But I need to place some setup code to initialize the library. So I need to get the render device context from Unity and acces to the main rendering loop so I can set specific library params before rendering everything.

Anyway to have access to main rendering loop and rendering device context?

Thank you for your feedback.

Any luck with this at all? I am in a very similar predicament.