I just need to know how to detect when a openend Carplay app, is back from background to reload data. Is there any way to detect it, like in iOS apps? Thanks in advance ;)

I’m working in a App using Swift that includes PencilKit with a “canvasview” to take notes. Everything works fine, but I can’t find the way to “convert” de value returned by canvasView.drawing to String for uploaded it and storage into a database.I can get a image and even a "base64EncodedString” but I need a way to send the “drawing” to a server and then load from it, and show in the canvasView.I have tested to convert it into a json, but I can’t “deserialize” and convert it into a “drawing” again, when is loaded from the server hehe.Thanks in advance