Function core::slice::sort::provide_sorted_batch

fn provide_sorted_batch<T, F>(
    v: &mut [T],
    start: usize,
    end: usize,
    is_less: &mut F
) -> usizewhere
    F: FnMut(&T, &T) -> bool,

🔬This is a nightly-only experimental API. (slice_internals)

Takes a range as denoted by start and end, that is already sorted and extends it to the right if necessary with sorts optimized for smaller ranges such as insertion sort.