Function plan_int_chunks 

pub fn plan_int_chunks(
    from: i64,
    to: i64,
    chunk_size: u64,
    bounds: Bounds,
) -> CliResult<Vec<IntChunk>>

Split [from, to] (or [from, to) per bounds) into contiguous chunks of at most chunk_size values.

The union of the returned chunks tiles the range exactly once — no gap, no overlap — under either bounds, which is the property the tests pin.