Bun's unreleased Rust port has 13,365 unsafe blocks

Bun's unreleased Rust port contains 13,365 unsafe blocks, with approximately two-thirds stemming from performance optimization, a Zig port, and FFI (Foreign Function Interface) boundaries. Analysis shows that roughly 9,300 unsafe blocks could potentially be replaced with safe code, while around 4,000 would need to remain unsafe behind wrappers. The density of unsafe code in Bun is notably higher than comparable runtimes like Deno, primarily because Bun consolidates its C bindings and runtime in a single workspace rather than separating them.