fix: UBs

[laysakura]

Issue number and link

Fixes: #60

Fixes: #49

Describe your changes

• Add rust integration tests.
• Locally run MIRI and remove UBs detected through the tests.
• Fix example to follow the new API.

Checklist before requesting a review

• I follow the Semantic Pull Requests rules (bugfix/feature)
• I specified links to related issues (must: bugfix, want: feature)
• I have performed a self-review of my code (bugfix/feature)
• I have added thorough tests (bugfix/feature)
• I have edited ## [Unreleased] section in CHANGELOG.md following keep a changelog syntax (bugfix/feature)
• I {made/will make} a related pull request for documentation repo (feature)