{"ast_node_type":"function","tokens":[{"end":51,"kind":"keyword","start":0,"text":"fn"}]}
fn parse_to_newline(buf: &[u8]) -> (&[u8], &[u8]) {
/// residual.
    buf.iter().position(|ch| *ch == b'\n').map_or((buf, &[]), |pos| buf.split_at(pos))