Resumable Iterator with Save / Restore State

Requirements Create an iterator class that provides at least the following behavior: next__() returns the next item and moves the iterator forward. save_state() → bytes dict produces a serializable snapshot that is sufficient to continue later. restore_state(state)—or an equivalent factory such as from_state(...)—reconstructs an iterator that resumes at exactly the saved position and preserves deterministic ordering. The implementation must work with arbitrary underlying…