Emitted when the download is in a terminal state. This includes a completed download, a cancelled download (via downloadItem.cancel()), and interrupted download that can't be resumed.The state can be one of following:* completed - The download completed successfully.* cancelled - The download has been cancelled.* interrupted - The download has interrupted and can not resume.

Emitted when the download has been updated and is not done.The state can be one of following:* progressing - The download is in-progress.* interrupted - The download has interrupted and can be resumed.