src/vs/platform/userDataSync/common/userDataSyncServiceIpc.ts/UserDataSyncChannelClient/call
class UserDataSyncChannelClient:	async createManualSyncTask(): Promise<IUserDataManualSyncTask> {
		const id = await this.channel.call<string>('createManualSyncTask');
		const that = this;
		const manualSyncTaskChannelClient = new ManualSyncTaskChannelClient(id, {
			async call<T>(command: string, arg?: any, cancellationToken?: CancellationToken): Promise<T> {
				return that.channel.call<T>(`manualSync/${command}`, [id, ...(Array.isArray(arg) ? arg : [arg])], cancellationToken);
			},
			listen<T>(): Event<T> {
				throw new Error('not supported');
			}
		});
		return manualSyncTaskChannelClient;
	}