start method
Implementation
DownloadProgressSession start({
String label = '',
int stepCount = 3,
String? key,
}) {
final active = _active;
if (key != null && active != null && _activeKey == key) {
return active;
}
_lastFinished?.dispose();
_lastFinished = null;
_active?.dispose();
final session = DownloadProgressSession(
initialLabel: label,
stepCount: stepCount,
);
_active = session;
_activeKey = key;
revision.value++;
return session;
}