Function render_background_lanes 

pub(crate) fn render_background_lanes(
    stages: &[&CuExecutionStep],
    entities: &[PlanEntity],
    pools: &[BackgroundPoolView<'_>],
    triggers: &[BackgroundTrigger<'_>],
    block_start: usize,
    block_end: usize,
    top: f64,
) -> RenderedSection