How do I send a JSON from unity?

[clearly-outsane]

I'm sorry but there doesn't seem to be a clear explanation to this on the README

UnityMessageManager.Instance.SendMessageToRN(new UnityMessage() { name = "click", callBack = (data) => { Debug.Log("onClickCallBack:" + data); } });

When i do this from unity, nothing happens on the react native side, the function passed to onUnityMessage doesnt get triggered