Instead of having to do something like
FlexItem::Margin margin(10.0);
margin.bottom = 0.0;
flexBox.items.add (FlexItem(header)
.withHeight(100.0)
.withFlex(0.15)
.withMargin(margin));
flexBox.items.add (FlexItem(body)
.withFlex(0.75)
.withMargin(10.0));
It would flow much nicer if we could have a detailed initialiser and do e.g.
flexBox.items.add (FlexItem(header)
.withHeight(100.0)
.withFlex(0.15)
.withMargin({10.0, 10.0, 10.0, 0.0})); // left, top, right, bottom
flexBox.items.add (FlexItem(body)
.withFlex(0.75)
.withMargin(10.0));