MainAxisAlignment mainAxisAlignment

How the children should be placed along the main axis.

Source 

MainAxisAlignment get mainAxisAlignment => _mainAxisAlignment;
void mainAxisAlignment=(MainAxisAlignment value)

Source 

set mainAxisAlignment (MainAxisAlignment value) {
  assert(value != null);
  if (_mainAxisAlignment != value) {
    _mainAxisAlignment = value;
    markNeedsLayout();
  }
}