CustomMultiChildLayout({Key key, @required MultiChildLayoutDelegate delegate, List<Widget> children: const [] })

Creates a custom multi-child layout.

The delegate argument must not be null.

Source 

CustomMultiChildLayout({
  Key key,
  @required this.delegate,
  List<Widget> children: const <Widget>[],
}) : super(key: key, children: children) {
  assert(delegate != null);
}