Function record 

pub fn record(
    module: &str,
    func: &str,
    loaded: bool,
    site: &'static Location<'static>,
)

Record one kernel lookup. Cheap; called from GpuBackend::kernel.

site is the caller’s Location, which the backend obtains from its own #[track_caller] frame — this function cannot take it implicitly, because its own caller is the backend, not the dispatch site.