delegate property

SingleChildLayoutDelegate delegate

A delegate that controls this object's layout.

Implementation 

SingleChildLayoutDelegate get delegate => _delegate;
void delegate= (SingleChildLayoutDelegate newDelegate)

Implementation 

set delegate(SingleChildLayoutDelegate newDelegate) {
  assert(newDelegate != null);
  if (_delegate == newDelegate)
    return;
  final SingleChildLayoutDelegate oldDelegate = _delegate;
  if (newDelegate.runtimeType != oldDelegate.runtimeType || newDelegate.shouldRelayout(oldDelegate))
    markNeedsLayout();
  _delegate = newDelegate;
  if (attached) {
    oldDelegate?._relayout?.removeListener(markNeedsLayout);
    newDelegate?._relayout?.addListener(markNeedsLayout);
  }
}