It would be very useful for unit testing embeddings built on embedder.h (such as the desktop embeddings) to be able to intercept calls to the entire embedder.h API surface (to ensure calls are made as expected, to return dummy responses, etc.). This would allow testing the embeddings as units, rather than being full stack tests that rely on bringing up the entire engine, Dart VM, etc.

Based on discussion with @chinmaygarde it sounds like what we want to do is allow clients to get/modify/set a jump table for all the embedder.h functions.