Function render_scene_output_with_progress 

pub fn render_scene_output_with_progress(
    scene: &Scene,
    setup: &RenderSetup,
    output: &Output,
    buffer_count: usize,
    on_progress: Option<Box<dyn Fn(u64, u64) + Send>>,
)

Available on crate feature cmd-render and non-target_family=wasm only.

Render one output with optional progress callback.

The callback receives (current_frame, total_frames) each frame.