Usage is kinda different for this one. You don’t need to define getActualSet, etc. Just define an option as: 
{
    optionType: 'spacer',
    title: string,
    description: string
}
​
title
string
required
Title string for spacer. You can use HTML there.
​
description
string
required
Description string for spacer. You can use HTML there.

​
Example Usage

{
    optionType: SoftUI.formTypes.spacer(),
    title: 'Spacer!',
    description: 'This is just spacing and even not an option, but yeah! Cool 😎'
}