{"ast_node_type":"variable","tokens":[{"end":46,"kind":"keyword","start":0,"text":"let"}]}
    let n = str::from_utf8(&buf[..pos]).ok()?;
    let pos = buf.iter().take(10).position(|ch| *ch == b'.')?;
    if !buf.get(pos + 1)?.is_ascii_whitespace() {