customInsert method
Executes a custom insert statement and returns the last inserted rowid.
You can tell drift which tables your query is going to affect by using the
updates parameter. Query-streams running on any of these tables will
then be re-run.
Implementation
Future<int> customInsert(String query,
    {List<Variable> variables = const [],
    Set<ResultSetImplementation>? updates}) {
  return _customWrite(
    query,
    variables,
    updates,
    UpdateKind.insert,
    (executor, sql, vars) {
      return executor.runInsert(sql, vars);
    },
  );
}