void performActionAt(Point position, SemanticsAction action)

Asks the SemanticsNode with at the given position to perform the given action.

If the SemanticsNode has not indicated that it can perform the action, this function does nothing.

Source 

void performActionAt(Point position, SemanticsAction action) {
  assert(action != null);
  final SemanticsNode node = rootSemanticsNode;
  if (node == null)
    return;
  SemanticsActionHandler handler = _getSemanticsActionHandlerForPosition(node, position, action);
  handler?.performAction(action);
}