Add custom data to Activity:info

Hi, I'm developing a data field to send garmin data to an external BLE device. The data is captured in the Activity::info object in the compute() call. Now I would like to add a custom data in addition to the standard garmin data to the BLE device and the easiest approach would be to just add the custom data as a new member of the Activity::info class. However, I have no idea how to do that and if it's even possible. Ideally just adding a new data member to the info struct, something like: 

info.add("myCustomData", value) 

Is that possible, in any way? 

TIA

//Fredrik