bool debugAssertAllWidgetVarsUnset(String reason)

Returns true if none of the widget library debug variables have been changed.

This function is used by the test framework to ensure that debug variables haven't been inadvertently changed.

See https://docs.flutter.io/flutter/widgets/widgets-library.html for a complete list.

Source 

bool debugAssertAllWidgetVarsUnset(String reason) {
  assert(() {
    if (debugPrintRebuildDirtyWidgets ||
        debugPrintBuildScope ||
        debugPrintScheduleBuildForStacks ||
        debugPrintGlobalKeyedWidgetLifecycle ||
        debugProfileBuildsEnabled) {
      throw new FlutterError(reason);
    }
    return true;
  });
  return true;
}