code: function shutdown() {
    ee.emitAsync('shutdown_server')
      .then(() => ee.emitAsync('shutdown_service'))
      .then(() => {
        ee.emit('shutted_down');
      })
      .catch((err) => {
        ee.emit('error', err); // TODO [ERR2BTERR] Maybe err -> BootError(err)
      });
  }
docs: Shutdown the kernel by closing the server and services
  to gracefully shutdown the application. To do that
  emits 2 async events; 'shutdown_server' and
  'shutdown_service'. After the listeners
  of those events were settled, emits
  'shutted_down' event (sync).