addView method
addView:inGravity:
Implementation
void addView(NSView view, {required NSStackViewGravity inGravity}) {
objc.checkOsVersionInternal(
'NSStackView.addView:inGravity:',
iOS: (true, null),
);
_objc_msgSend_ldu1k5(
this.ref.pointer,
_sel_addView_inGravity_,
view.ref.pointer,
inGravity.value,
);
}