fn get_offsets_for_flatten<O: OffsetSizeTrait, P: OffsetSizeTrait>(
inner_offsets: OffsetBuffer<O>,
outer_offsets: OffsetBuffer<P>,
) -> OffsetBuffer<O>fn get_offsets_for_flatten<O: OffsetSizeTrait, P: OffsetSizeTrait>(
inner_offsets: OffsetBuffer<O>,
outer_offsets: OffsetBuffer<P>,
) -> OffsetBuffer<O>