As much as I'm looking forward to 4, has GDExtension been stabilized / documented yet? I know there's the existing C++ example [1], but I really, really don't want to jump through a scons & C++ project simply to call a single native function in a DLL. You can do such a thing with GDNative, and I presume that it is possible in GDExtension as well, though it isn't obvious how to do so. This strikes me as a huge barrier to adoption, since GDNative is one of the big things that will be incompatible with 4.
[1] In the godot-cpp library: https://github.com/godotengine/godot-cpp