src/vs/platform/userDataSync/common/userDataSyncService.ts/UserDataSyncService/performSynchronizerAction
class UserDataSyncService:	private async performSynchronizerAction<T>(action: (synchroniser: IUserDataSynchroniser) => Promise<T | undefined>): Promise<T | null> {
		const disposables = new DisposableStore();
		try {
			const synchronizers = this.synchronizers.value || disposables.add(this.instantiationService.createInstance(Synchronizers, () => { }, () => { }, () => { }));
			const allSynchronizers = [...synchronizers.enabled, ...synchronizers.disabled.map(syncResource => disposables.add(synchronizers.createSynchronizer(syncResource)))];
			for (const synchronizer of allSynchronizers) {
				const result = await action(synchronizer);
				if (!isUndefined(result)) {
					return result;
				}
			}
			return null;
		} finally {
			disposables.dispose();
		}
	}