pub fn start_webgpu_thread(
compositor_api: CrossProcessCompositorApi,
external_images: Arc<Mutex<WebRenderExternalImageRegistry>>,
wgpu_image_map: WGPUImageMap,
) -> Option<(WebGPU, IpcReceiver<WebGPUMsg>)>pub fn start_webgpu_thread(
compositor_api: CrossProcessCompositorApi,
external_images: Arc<Mutex<WebRenderExternalImageRegistry>>,
wgpu_image_map: WGPUImageMap,
) -> Option<(WebGPU, IpcReceiver<WebGPUMsg>)>