Example for a CSHS-enabled term reference field on a custom form?

I ended up generating options like this but please comment if there is a better way. Thanks.

$term_options = [];
$terms = \Drupal::entityTypeManager()->getStorage('taxonomy_term')->loadTree('vid-name',0,NULL,TRUE);
foreach ($terms as $term) {
	$termId = $term->id();
	if($term->parent->target_id) {
		$term_options[$termId] = new CshsOption($term->getName(),$term->parent->target_id);
	} else {
		$term_options[$termId] = new CshsOption($term->getName());
	}
}

Thanks @dmudie! This was really helpful.

I still wonder if there's a cleaner way to do this.