echidna 0.9.0

A high-performance automatic differentiation library for Rust
Documentation
## Summary

Brief description of changes.

## Changes

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## Test Plan

How were these changes tested?

## Checklist

- [ ] Tests pass (`cargo test`)
- [ ] No clippy warnings (`cargo clippy -- -D warnings`)
- [ ] Code formatted (`cargo fmt --check`)
- [ ] Documentation updated if needed
- [ ] CHANGELOG.md updated for user-facing changes