Standard way to annotate ffi.cdef

I have some ffi that looks like this

---@type ffilib
Connector.ffi = package.preload["ffi"]()
Connector.ffi.cdef [[
	 void curl_free_pointer(const char* string);
   const char* curl_get(const char* query);
   const char* curl_patch(const char* query, const char* body, bool return_patched);
   const char* curl_post(const char* query, const char* body, bool merge_duplicates, bool ignore_duplicates, bool return_post);
]]

I am able to get nice typing on the Connector.ffi part through ---@type ffilib, but am not sure if there is a nice way to annotate the returns from these functions. A could wrap the c functions to lua functions and then annotate the lua functions, but I wasn't sure if there was a nice way to do it directly.

Start by reviewing how ffi.cdef and the ffilib type are currently handled, then trace whether return types can be represented directly in that path. Done means there is a documented annotation approach for these C functions, with coverage showing that their return types are recognized without Lua wrapper functions.