onAdd method
Implementation
void onAdd(DropdownOption<T> option) {
if (_options.containsKey(option.value.hashCode)) {
return;
}
_options.putIfAbsent(option.value.hashCode, () {
_searchController.clear();
return option;
});
if (widget.dismissOnAdd) {
_popupController.hide();
}
widget.onChanged(_options.values.toList());
_debounceSetOptions();
}