syntax_data: {"ast_node_type":"function","tokens":[{"end":75,"kind":"keyword","start":0,"text":"fn"}]}
source_snippet:     fn coroutine_is_async_gen(self, coroutine_def_id: Self::DefId) -> bool;
context_before:     fn coroutine_is_gen(self, coroutine_def_id: Self::DefId) -> bool;