Function render_to_rgba 

pub fn render_to_rgba(
    list: &DisplayList,
    pixel_w: u32,
    pixel_h: u32,
    dpi: f64,
    icc: Option<&IccCache>,
    no_aa: bool,
) -> Vec<u8> 

Render a full-page display list to RGBA pixels using the banded parallel renderer.

This is the preferred way to render a complete page — it uses rayon parallelism (when the parallel feature is enabled) and L2-cache-friendly band sizing. For sub-region / zoomed viewport rendering, use render_region instead.

Returns RGBA pixel data of size pixel_w × pixel_h × 4, composited onto white.