public Long getSubscriptionId() {
        return subscriptionId;
    }
Registers a new Consumer, this allows multiple PLC4X consumers to use the same subscription.

@param consumer - Consumer to be used to send any returned values.
@return PlcConsumerRegistration - return the important information back to the client.
plc4j/drivers/opcua/src/main/java/org/apache/plc4x/java/opcua/protocol/OpcuaSubscriptionHandle.java