function customForward<T>({ from, to }: { from: Unit<T>; to: Unit<T> }): Function {
  return (from as any).watch((payload: T) => {
    const _to = to as any;
    if (typeof to === 'function') {
      _to(payload);
    } else {
      _to.setState(payload);
    }
  });
}

forward({
    from: combine({
      socket: $socket,
      headers: $echoAuthHeaders,
      isConnected: $isConnected,
      channel: restore<ChannelName>(channel as any, null),
    }),
    to: subscribeFx,
  });