message: Skip deep change checking for tables with no outgoing links
  The tracking of which rows *aren't* modified (to avoid rechecking if a row has
  multiple incoming links) ends up being a sizeable portion of the runtime in
  this case and is completely pointless, so just skip it.
diff: @@ -44,6 +44,10 @@ CollectionNotifier::get_modification_checker(TransactionChangeInfo const& info,
  if (!any_of(begin(m_related_tables), end(m_related_tables), table_modified)) {
  return [](size_t) { return false; };
  }
  + if (m_related_tables.size() == 1) {
  + auto& modifications = info.tables[m_related_tables[0].table_ndx].modifications;
  + return [&](size_t row) { return modifications.contains(row); };
  + }
  return DeepChangeChecker(info, root_table, m_related_tables);
  }
  