{"ast_node_type":"function","tokens":[{"end":77,"kind":"keyword","start":0,"text":"fn"}]}
    fn set_type_metadata(&self, _function: Self::Function, _typeid: &[u8]) {}
    fn add_type_metadata(&self, _function: Self::Function, _typeid: &[u8]) {}
    fn typeid_metadata(&self, _typeid: &[u8]) -> Option<Self::Metadata> {