Function fire 

pub(crate) fn fire(message: &str, source: PanicSource)

Fire the telemetry hook if one is set.

Called internally at each panic→R-error conversion site.

The hook is cloned (as Arc) and the lock is dropped before invocation, so the hook can safely call set_panic_telemetry_hook or clear_panic_telemetry_hook without deadlocking. Secondary panics from the hook are caught and silently suppressed.