I hope the API can add a metadata change listening interface

[m1509001]

希望 api 增加元数据变化监听接口，比如：
元数据添加 onPropertyValueAdd(callback)
元数据属性修改onPropertyNameChange(callback)
元数据值修改onPropertyValueChange(callback)
元数据删除onPropertyValueRemove(callback)

I hope the API can add a metadata change listening interface, such as:
adding metadata onPropertyAdd (callback)
modifying metadata onPropertyValueChange (callback)
modifying metadata onPropertyNameChange (callback)
deleting metadata onPropertyRemove (callback)