Tab 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. The iconMargin is only useful when icon and either one of text or child is non-null.
Implementation
const Tab({
super.key,
this.text,
this.icon,
this.iconMargin,
this.height,
this.child,
}) : assert(text != null || child != null || icon != null),
assert(text == null || child == null);