src/vs/platform/userDataSync/common/abstractSynchronizer.ts/AbstractSynchroniser/getUserData
class AbstractSynchroniser:	private async getUserData(refOrLastSyncData: string | IRemoteUserData | null): Promise<IUserData> {
		if (isString(refOrLastSyncData)) {
			const content = await this.userDataSyncStoreService.resolveContent(this.resource, refOrLastSyncData);
			return { ref: refOrLastSyncData, content };
		} else {
			const lastSyncUserData: IUserData | null = refOrLastSyncData ? { ref: refOrLastSyncData.ref, content: refOrLastSyncData.syncData ? JSON.stringify(refOrLastSyncData.syncData) : null } : null;
			return this.userDataSyncStoreService.read(this.resource, lastSyncUserData, this.syncHeaders);
		}
	}