Function polars_io::utils::get_sequential_row_statistics

pub fn get_sequential_row_statistics<I>(
    iter: I,
    total_rows_to_read: usize
) -> Vec<(usize, usize)>
where
    I: Iterator<Item = usize>,

Compute remaining_rows_to_read to be taken per file up front, so we can actually read concurrently/parallel

This takes an iterator over the number of rows per file.