Bun's unreleased Rust port contains 13,365 unsafe blocks, most of which are removable

Bun's unreleased Rust port has 13,365 unsafe blocks. Most can be removed.

Density tracks how close the code sits to a C boundary: a crate that only binds a C++ engine is densest, a runtime that writes its own engine in Rust is sparsest.

Bun keeps its bindings and runtime in one workspace; Deno splits the binding into rusty_v8 and writes much of its runtime in TypeScript.