Include ability to keep particles by volume in next release
As discussed in the larsoft coordination meeting and here (https://indico.fnal.gov/getFile.py/access?contribId=3&resId=0&materialId=slides&confId=10893) MicroBooNE would like the following feature branches included in the next release:
This adds the fcl parameter KeepParticlesInVolumes to LArG4_module.cc to allow a list of volume names to be specified. If a g4 particle passes through one of these volumes (has a trajectory point contained in the volume) then that particle is kept, otherwise it is not stored. This reduces the memory and disk usage and tests in MicroBooNE have shown that it does not significantly affect analyses.
If no volumes are specified (default) then all particles are kept so this is a non-breaking change.