set_difference(from.cbegin(), from.cend(), to.cbegin(), to.cend(), back_inserter(diff->removals), from.value_comp());
set_difference(to.cbegin(), to.cend(), from.cbegin(), from.cend(), back_inserter(diff->additions), from.value_comp());
diff->oldSOA = fromSOA;
set_difference(from.cbegin(), from.cend(), to.cbegin(), to.cend(), back_inserter(diff->removals), from.value_comp());
set_difference(to.cbegin(), to.cend(), from.cbegin(), from.cend(), back_inserter(diff->additions), from.value_comp());
diff->oldSOA = fromSOA;