struct in UnityEngine.Experimental.UIElements
Hierarchy is a sctuct allowing access to the shadow hierarchy of visual elements
| childCount | Number of child elements in this object's contentContainer |
| parent | Access the physical parent of this element in the hierarchy |
| this[int] | Access to this element physical hierarchy |
| Add | Add an element to this element's contentContainer |
| Children | Returns the elements from its contentContainer |
| Clear | Remove all child elements from this element's contentContainer |
| ElementAt | Retrieves the child element at position |
| Insert | Insert an element into this element's contentContainer |
| Remove | Removes this child from the hierarchy |
| RemoveAt | Remove the child element located at this position from this element's contentContainer |
| Sort | Reorders child elements from this VisualElement contentContainer. |