src/vs/platform/userDataSync/common/userDataSyncStoreService.ts/UserDataSyncStoreClient/addSessionHeaders
class UserDataSyncStoreClient:	private addSessionHeaders(headers: IHeaders): void {
		let machineSessionId = this.storageService.get(MACHINE_SESSION_ID_KEY, StorageScope.APPLICATION);
		if (machineSessionId === undefined) {
			machineSessionId = generateUuid();
			this.storageService.store(MACHINE_SESSION_ID_KEY, machineSessionId, StorageScope.APPLICATION, StorageTarget.MACHINE);
		}
		headers['X-Machine-Session-Id'] = machineSessionId;

		const userSessionId = this.storageService.get(USER_SESSION_ID_KEY, StorageScope.APPLICATION);
		if (userSessionId !== undefined) {
			headers['X-User-Session-Id'] = userSessionId;
		}
	}