Glutin OpenGL context in macOS/iOS app

I'm looking to use Rust to create cross-platform code and graphical elements, via static/dynamic libraries for use in otherwise "native" built apps, initially for macOS and iOS but also for Windows, Android and Linux.

I'm trying out Conrod as a graphics library, and looking for example code that either passes an OpenGL context from a Cocoa app to glium to draw onto, or create one with glutin and pass a pointer to it back to the Cocoa app. I'm familiar with how to do this sort of thing using the JUCE C++ library. I'm evaluating using Rust instead of C++ for an upcoming project.

Are there any examples of this kind of project structure around?