syntax_data: {"ast_node_type":"variable","tokens":[{"end":74,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let mut hash = SourceFileHash { kind, value: Default::default() };
context_before:     pub fn new(kind: SourceFileHashAlgorithm, src: impl Read) -> Result<SourceFileHash, io::Error> {
context_after:         let len = hash.hash_len();