How godot handles RSS memory?

Godot Version

Godot 3.5

Question

Hello, I’m trying to determine how much memory my project is using. Specifically, I’m looking to compare the memory usage of different file formats, so I modified the following function:

RES ResourceLoader::load(const String &p_path, const String &p_type_hint, bool p_no_cache, Error *r_error)

Within this function, I implemented something like this:

Performance::get_singleton()->CheckMemSizeBeforeLoad();
RES res = _load(path, local_path, p_type_hint, p_no_cache, r_error);
Performance::get_singleton()->CheckMemSizeAfterLoad(path.get_extension());

Using this, I gathered some data, but the results seem a bit off. To improve accuracy, I added a check for whether the resource is already cached:

Performance::get_singleton()->CheckMemSizeBeforeLoad();
ResourceCache::lock.read_unlock();
_remove_from_loading_map(local_path);
Performance::get_singleton()->CheckMemSizeAfterLoad(path.get_extension());

With this modification, the data appears more consistent when compared to other systems I have in the project. However, .tscn files show as occupying no memory, which seems incorrect.

How i could know how to correctly measure memory usage for different resource types and whether there is a better approach for calculating this?