What is the correct way to determine whether there are uncancelled entries for a given upload? I noticed that a cancelled entry for a given upload, completed or incomplete, has a key/value pair of cancelled?: true. I am not sure if this is documented anywhere or if the key is part of the public interface for the Phoenix.Liveview.UploadEntry struct. However, it looks like one can manually traverse the list of completed and incomplete entries checking for an entry with cancelled?: false to detect whether all entries were cancelled. It just feels like there should be a public API for detecting this. Am I completely off in my thinking?