message: extend vector<map<>> safely
diff: @@ -36,7 +36,7 @@ public:
  const std::vector<std::string>& triggerNames);
  map_type& GetMap(std::size_t iScan) {
  - if (iScan >= fData.size())
  + for (; iScan >= fData.size();)
  fData.emplace_back(map_type());
  return fData[iScan];
  }
  