Summary

Replace Option<int> with optional::Optioned<int> in native objects to save memory to enhance performance.

Detailed Explanation

In many cases, our usize means u63/u31 rather than u32/u64 because sys.maxsize is isize::MAX.
Unfortunately, we are not telling this to compiler very well.
For example, Option<usize> for None or u63 is a common type in RustPython. But its memory size if 16 rather than 8
https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=cdbd4b4bcc01d81b57f8d9040901e107

By replacing it to optional::Optioned<usize>, it will go back to 8, the proper size of its actual representation.
https://docs.rs/optional/

Drawbacks, Rationale, and Alternatives

Unresolved Questions