When does ES_EVENT_TYPE_NOTIFY_FILE_PROVIDER_UPDATE event get raised

Description says this event will be raised when "An identifier for a process that notifies endpoint security that it is updating a file." What does this mean ? Similarly when will ES_EVENT_TYPE_NOTIFY_FILE_PROVIDER_MATERIALIZE event be raised ?

Do these events get raised if any cloud provider sync app like Google Drive/Dropbox/OneDrive that usages fileprovider framework to sync the data ?

In my endpoint secutiry app, I have registered for these events but i didnt receive any event *i do receive other endpoint secutiry events like ES_EVENT_TYPE_NOTIFY_CLONE etc.