th, callback) {
      fetch(path)
        .then(function(response) {
          return response.json();
        })
        .then(function(json) {
            callback(json);
        });
    }
  </script>
  <script type=module>
    let client
    let updateScheduled = false

    window.GlobalJS = function () {}
    // TODO:
    // https://rustwasm.github.io/wasm-bindgen/api/web_sys/struct.Window.html#method.request_animation_frame
    window.GlobalJS.prototype.update = function () {
      if (!updateScheduled