The service descrciption can be found in the OICP 2.1.

Section:
3.1.3 eRoamingAuthorizeRemoteStart

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/**
 * Initiate a remote start of the given charging session at the given EVSE
 * and for the given Provider/eMAId.
 *
 * @param Timestamp The timestamp of the request.
 * @param RoamingNetworkId The unique identification for the roaming network.
 * @param SessionId The unique identification for this charging session.
 * @param PartnerSessionId The unique identification for this charging session on the partner side.
 * @param ProviderId The unique identification of the e-mobility service provider.
 * @param eMAId The unique identification of the e-mobility account.
 * @param EVSEId The unique identification of an EVSE.
 * @param ChargingProductId The unique identification of the choosen charging product at the given EVSE.
 * @return A remote start result object.
 */
public RemoteStartResult Invoke(Instant             Timestamp,
                                RoamingNetwork_Id   RoamingNetworkId,
                                ChargingSession_Id  SessionId,
                                ChargingSession_Id  PartnerSessionId,
                                EVSP_Id             ProviderId,
                                eMA_Id              eMAId,
                                EVSE_Id             EVSEId,
                                ChargingProduct_Id  ChargingProductId);


/**
 * Register an event callback for incoming remote start requests.
 *
 * @param RemoteStartHandler an implementation of the remote start functional interface.
 */
public void OnRemoteStart(IRemoteStart RemoteStartHandler)
{ ... }

CPOServer HubjectCPOServer = new CPOServer(RoamingNetwork_Id.Parse("Playground"));

HubjectCPOServer.OnRemoteStart((Timestamp,
                                RoamingNetworkId,
                                SessionId,
                                PartnerSessionId,
                                ProviderId,
                                eMAId,
                                EVSEId,
                                ChargingProductId) -> {

    System.out.println("[" + Timestamp.                            toString() +
                          "] RemoteStart in '" + RoamingNetworkId. toString() +
                          "' from '"           + ProviderId.       toString() +
                          "' for '"            + eMAId.            toString() +
                          "' at '"             + EVSEId.           toString() +
                          "' / '"              + ChargingProductId.toString() +
                          "'");

    return RemoteStartResult.Success;

});