syntax_data: {"ast_node_type":"other","tokens":[{"end":76,"kind":"keyword","start":0,"text":"///"}]}
source_snippet: /// - `len` is ~15 bits in `Span` (a u16, minus 1 bit for PARENT_TAG) and 32
context_before: ///   if a crate exceeds a particular size.
context_after: ///   bits in `SpanData`, which means that large `len` values will cause