Represents a metadata item associated with Metadata
Gets or sets a value indicating whether this metadata item is currently open. When an item is open, its child items (if any) are visible. This property is observable.
Gets the list of metadata items contained in this group. This property is observable.
Gets or sets the name of the metadata item. This property is observable.
Gets or sets the value of the metadata item.
MetadataItem#isOpen property. If this item's list of children is open,
calling this method will close it. If the list is closed, calling this method will open it.