Function csv_row_spans 

pub fn csv_row_spans(path: impl AsRef<SPath>) -> Result<Vec<(usize, usize)>>

CSV-aware record spans: returns byte ranges [start, end) for each row.

• Treats ‘\n’ as a record separator only when not inside quotes.
• For CRLF, the ‘\r’ is excluded from the end bound.
• Supports "" as an escaped quote inside quoted fields.
• Streams in chunks; does not read the whole file into memory.