syntax_data: {"ast_node_type":"function","tokens":[{"end":68,"kind":"keyword","start":0,"text":"fn"}]}
source_snippet: fn asyncness(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Asyncness {
context_before: /// Check if a function is async.
context_after:     let node = tcx.hir_node_by_def_id(def_id);