syntax_data: {"ast_node_type":"other","tokens":[{"end":20,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:     // `ByteSymbol`.
context_before:     // effectively pre-interning all these strings for both `Symbol` and
context_after:     fn prefill(init: &[&'static str], extra: &[&'static str]) -> Self {