AtlasHepMC: Fix thread-safety checker warning. (!66384) · Merge requests · atlas / athena · GitLab

Scott Snyder requested to merge ssnyder/athena:thread.AtlasHepMC-20231011 into main Oct 11, 2023

Fix thread-safety checker warning when compiling against hepmc2.

Barcode function should take a T const , not a T const &.