pub fn seek(&mut self, mut i: u64) -> CliResult<()> {
        if i >= self.count() {
            let msg = format!(
                "invalid record index {} (there are {} records)",
                i, self.count());
            return fail!(io::Error::new(io::ErrorKind::Other, msg));
        }
        if self.csv_rdr.has_headers() {
            i += 1;
        }
        let pos = self.idx.get(i)?;
        self.csv_rdr.seek(pos)?;
        Ok(())
    }
Seek to the starting position of record `i`.
src/index.rs