Queues files for folder; one validate turns away becomes a rejected row.
Why the file cannot be sent at all, or null.
Stops a file that is queued or being sent: the send is aborted, the row goes, and the list is never told of it. A file already being listed cannot be cancelled.
Drops a row that is no longer going anywhere.
ReadonlygetThe operator's answer for a name a file already holds.
Sends a failed file again from the start.
Readonlysubscribe
Uploads files a few at a time: sign,
PUT, then index. It holds no React state, so a host can keep one past the page that started an upload, and each file keeps the actions of the folder it was added to.