syntax_data: {"ast_node_type":"other","tokens":[{"end":75,"kind":"keyword","start":0,"text":"lo.update(new_file_and_idx,"}]}
source_snippet:                 lo.update(new_file_and_idx, span_data.lo, self.time_stamp);
context_before:                 let lo = &mut self.line_cache[oldest];
context_after:                 let hi = &mut self.line_cache[hi_cache_idx as usize];