This is an implementation of a new APR Storage Technology using ROOT RNTuple.
The eventual goal is to be able to use RNTuple in the same way as we use TTrees and TBranches now, simply by specifying the new StorageTech.
RNtuple Storage Technology can be enabled by setting this property: AthenaPoolCnvSvc::StorageTechnology Property to ROOTRNTUPLE (now ROOTTREEINDEX)
Things not working yet:
Build procedure: use asetup master--dev3LCG,latest,Athena
packages to build:
There is one RNTuple per original TTree, name is changed to RNT: