romise(r => {
                resolve = r;
            });
        }

        const resizeObserver = new ResizeObserver(entries => {
            for (let entry of entries) {
                const { width, height } = entry.contentRect;
                const borderBoxSize = entry.borderBoxSize[0];
                const contentBoxSize = entry.contentBoxSize[0];
                const deviceBoxSize = entry.devicePixelContentBoxSize[0];
                let string = `contentSize: ${width}px x ${height}px`;
       