[This is preliminary documentation and is subject to change.]
Adopts the given object as a child of this object, and sets it into into the member field passed as an IReference. In normal processing this is the ONLY place where parent of an object is set. This method is called in the set methods of persistent properties for contained object members. It is also called from IndexedList<(Of <(<'T>)>)> when objects are added to non contained collections. Any existing child object in this member is deleted from persistent storage. Note that child can be null, in which case nothing further is done. Otherwise the child's parent is set to this.