 element = new Map;
    const { Worker } = coincident();
    assign(new Worker('./worker.js', { serviceWorker: '../sw.js' }).proxy, {
        createElement(tree) {
            promote(tree);
            element.set(id, createElement(tree));
            return id++;
        },
        appendElement(where, ...elements) {
            const parent = document.querySelector(where);
            parent.append(...elements.map(({ id }) => element.get(id)));
        },
        patchElement(patches, { id }) {
         