Loading of existing data set without going through string conversions
It is possible to load an existing data set for some post-processing job using InputCppRoot. This algorithm does a conversion to json format as part of the load process. The conversion is necessary as the Inputter can sometimes like to load JobHeader events, sometimes RunHeader events, sometimes Spill events, etc.
Actually, for most analyses we don't really care to load the header and footers, we really only want the Spill data. In this case, a specialist inputter would be faster that did direct load of the C++ data without mucking about with json conversion.