syntax_data: {"ast_node_type":"function","tokens":[{"end":75,"kind":"keyword","start":0,"text":"pub"}]}
source_snippet:     pub fn time<R>(&self, what: &'static str, f: impl FnOnce() -> R) -> R {
context_before:     /// Used by `-Z self-profile`.
context_after:         self.prof.verbose_generic_activity(what).run(f)