Basic example of using BrowserEngineKit extension APIs to start and perform an operation in a child process, using a shared Framework between both the content extension and the main application.
Unfortunately, currently when building this app will end up creating 2 copies of the EngineCommon shared framework and all of its resources, one for the main application and one for the WebContent extension. If the other extension types (Rendering and Networking) were also present, they would also get a full copy of the EngineCommon shared framework.
In an ideal world, the code in this shared framework would only be present in one location in the final app bundle and would be shared between the main process and all BrowserEngineKit extensions.