Refactoring Iter constructor
Refactoring Iter constructor

Cherrypicked from d54a74a3050efda9687269feec5334a2a0bebf02 by @IcanDivideBy0

Co-authored-by: Samuel Hurel <bf2f71fa4ca47ce4924dc1dcca5fe9b9d4c56850@gmail.com>

gltf-rs/gltf