src/vs/platform/userDataSync/common/userDataSyncService.ts/UserDataSyncService/hasPreviouslySynced
class UserDataSyncService:	async hasPreviouslySynced(): Promise<boolean> {
		for (const synchroniser of this.synchronisers) {
			if (await synchroniser.hasPreviouslySynced()) {
				return true;
			}
		}
		return false;
	}