{"ast_node_type":"variable","tokens":[{"end":56,"kind":"keyword","start":0,"text":"let"}]}
        let profiler_layer = match self.profile_filter {
        // TODO: remove `.with_filter(LevelFilter::OFF)` on the `None` branch.
            Some(spec) => Some(hprof::SpanTree::new(&spec)).with_filter(LevelFilter::INFO),