abortUpload method
abortUpload: ends an open own session; the file becomes failed (12 2).
Throws 404 and 409 invalid_state_transition for a completed session.
Implementation
void abortUpload(String principalId, String fileId) {
final f = _ownFile(principalId, fileId);
if (f.sessionState == 'completed') {
throw const FakeProblem(409, 'invalid_state_transition');
}
if (f.sessionState != 'open') return;
f
..sessionState = 'aborted'
..parts.clear();
f.json['upload_state'] = 'failed';
_fileUpdated(f);
}