Function render_rust_region_runtime 

pub fn render_rust_region_runtime(
    module_name: &str,
    token: &str,
    crate_key: &str,
    layout: &RustProbeLayout,
    crate_cfgs: &[usize],
) -> Result<String, String>

The region runtime for one crate root. Every crate of an instrumentation shares token and layout, so their copies map one region per process. crate_key names the crate’s exports where the region is static memory (wasm): each crate of a module keeps its own there.