src/vs/platform/userDataSync/common/userDataSyncService.ts/ManualSyncTask/reset
class ManualSyncTask:	private reset(): void {
		if (this.previewsPromise) {
			this.previewsPromise.cancel();
			this.previewsPromise = undefined;
		}
		this.previews = undefined;
		this.synchronizingResources = [];
	}