MagicTab constructor
Creates a material design TabBar tab.
At least one of text, icon, and child must be non-null. The text and child arguments must not be used at the same time.
Implementation
const MagicTab({
Key key,
this.text,
this.icon,
this.child,
this.tabHeight=46,
}) : assert(text != null || child != null || icon != null),
assert(!(text != null && null != child)), // TODO(goderbauer): https://github.com/dart-lang/sdk/issues/34180
super(key: key);