on2<A extends Comp<T> , B extends Comp<T> > method
Invokes callback with the first top-level components matching types
A and B, if both exist.
Implementation
E on2<
A extends Comp<T>,
B extends Comp<T>
>(
void Function(A, B) callback
) {
final a = get<A>(), b = get<B>();
if (a == null || b == null) return self;
callback(a, b);
return self;
}